My epiphany, so to speak, concerning this argument. It finally hit me that it really does boil down to the covenant argument. That the Ref. Bap. does not view or rest (in theory) their baptism primarily upon a profession of faith (arminian bap. & TULIP SB), though it (profession) is connected.
In theory baptism is viewed as valid only if applied to those truly regenerate, these are to the RB really and only in covenant and thus receive the sign. The false professors who happen to receive a baptism rite and later fall away are viewed as never having been in covenant and since only those truly in covenant receive the sign - their "œbaptism event" is considered false or invalid, hence not really a baptism at all. The problem still remain with the struggler who is not sure, and not the "œclear cut" cases though. In theory this sounds and is consistent. But cannot be in practice (below).

lol I bang my head because I feel as though I have made important and obvious statements in this thread in order to avoid this view (at least as I hold it). However, I am only doing so out of humor, because I know most Baptists (even "Reformed Baptists") may not agree with me, but I can sleep well at night knowing that.
Now you need to make a fourth category of Baptists, or make a division between the types of Reformed (confessional) Baptists. This particular Baptist (no pun intended) does *NOT* believe baptism is only "valid" if the person receiving it is regenerate during the time it is received (I introduced the terms "valid" and "regular" for a whole other reason). Let's say there are three types of people who are baptized:
1. Elect and regenerate at time of baptism.
2. Elect and unregenerate at time of baptism (regenerated at a later date necessarily because of God's election).
3. Reprobate and unregenerate at time of baptism (never regenerated because of God's reprobation).
Now, let's say I dunk this sucker who is #3. The baptism is still valid. That person, by virtue of baptism, has entered into the New Covenant (as separate from the CoG, which is entered into only through faith alone). This person, from the divine perspective, is a member of the New Covenant. However, only if this baptism is accomapnied by faith will it be efficacious unto salvation (in a manner of speaking of the means of grace in sanctification). This baptism will be efficacious unto greater condemnation if the sacrament is never accompanied by faith. It is valid either way for #3. Let's say I dunk a #2 candidate. The baptism, prior to personal faith, is valid, and that person is in the New Covenant, but it is not effectual unto salvation until this elect does have faith. Once this person has faith, the effectiveness of the sacrament is applied to him. The baptism prior to his faith is still "valid" (keeping in mind the distinctions of valid, invalid, regular, or irregular as discussed above). Person #1, when dunked, has the efficacy of baptism when applied with the accompaniment of the preached word because he already has faith. ALL THREE BAPTISM ARE VALID, but only two will salvifically efficacious, while the third (#3) will only be efficacious in a condemning manner. None of these three are ever to be baptized "again," if they are valid/regular or valid/irregular (to the exclusion of what I suggested regarding invalid/regular and invalid/irregular). Regardless of the person's faith at the time of baptism, the baptism is valid and the person is in covenant with God (much like the reprobate in Israel through circumcision, regardless of faith). Now, please, do not confused "valid" with "efficacious" in how I'm speaking.
In practice, however, true and flawless "œdetection" for a lack of a better word of a regenerate person is not possible 100% of the time. And seeking it at least teeters on passing judgment when conditions for seeking it are not met (this is a valid hazard). Later open rejectors that have had a baptism event are a simple cases and the minority report. But it is the struggler (or even the returning rejector) who presents the problem with the theory, since the heart cannot be seen and secondary causes in this case cannot guarantee the theory. This explains the sometimes over zealous search for fruit (esp. by the introspecting person struggling, in this sense the RB position is no different than the other AB and TULIP SB) - they are merely attempting to apply the theory as best they can, yet short of 100%. This is where we can tip over into paving a "œlegal pathway"œ. They wouldn´t call a second baptismal event baptism due to their definition of "œreal baptism". BUT the one struggling and seeking a "œsecond event" introspects and introspects attempting to find assurance in fruits that "œtell him" he is now "œreally saved" and can be baptized "œfor the first time". Rather than redirecting him back to Christ where true faith is and true assurance is. Basically the theory and practice cause an inherent conflict.
All of this applies to the dangers of paedobaptists who baptize the unchurched. This is a warning to us ALL, not merely Baptists. Paedobaptists can and do the same things with the converted, unchurched members. Both of us--paedo's and credo's--must be on guard against this.
The Paedeo community for adults does the same thing in baptizing the first time adults, but their view of covenant is more biblical in the sense of what we see throughout OT/NT. In that any covenant can contain both adherents and breakers of the covenant who equally receive the sign and the sign depends not on only those obedient to the covenant but includes both. So, that when they baptize adults they may examine them reasonably. Yet, if an adult baptized falls away, then returns the sign is not given again. Or if one is struggling they are not sent to wrestle with looking at their faith and fruit, but sent back to Christ and the promises.
I beg to differ.

I, as a Reformed Baptist, believe the New Covenant can and does contain non-elect who are truly in covenant with God through baptism. If, as a Reformed Baptist, a congregant falls away and comes back again, the sign is not to be given again, but we pray it is finally sealed with true faith.
Now, unfortunately, I think I am extremely rare as a Reformed Baptist, but, Lord willing, that will change as Reformed Baptist systematic and covenant theology is *FINALLY* developed.