So here's another issue that I feel deserves some serious attention. The conspiratorial view presented in the OP, and various other Futurist and Dispensationalist models is, effectively, that a piece of technology or a tattoo, or something of that nature cuts a person off from salvation forever. And that it is entirely possible for a person to take this mark unknowingly or in ignorance; thus a person could--without knowing what they are doing--get a microchip in their hand and that would render a person entirely outside of God's grace.
That doesn't bode very well for the Gospel. Effectively it means the Gospel is powerless, God's mercy is empty, and a person's salvation isn't based upon the efficacious and completed work of Jesus but on what one does (or, in this case, doesn't do). Got a microchip because it's a convenient piece of technology instead of using a debit card, well guess what you're now damned and there's nothing you can do about it, and your faith in Jesus and His saving work for you on the cross? Doesn't matter.
Conspiratorial nuttiness and a total butchery of the biblical texts aside, the most problematic aspect here is in its total rejection of Jesus Christ and the Gospel. If your theology and biblical interpretation means denying the Gospel then there's a problem, a massive problem.
But this kind of bogeyman pseudo-Eschatology is quite often an implicit (if not explicit) rejection of the Gospel. I'm willing to be generous and assume many who hold to these ideas simply have never bothered to think them through, and/or seriously considered the ramifications of such beliefs. But I would encourage people who call themselves Christians to bother to put in the effort of thinking through one's beliefs, critically. Because if Jesus is not at the center of what we believe, if our theology does not begin and end with Christ, then something's deeply wrong.
-CryptoLutheran