Didn't people 70 years ago think that social security number were the mark of the beast? At first the program was voluntary, but then became required . . . . the difference comes in the forced "either take the mark or you will be considered an enemy of the state" type mentality.
Personally, I would still avoid it and pray I never have to make that kind of decision - even though I know that, at this point in time, it is not the mark of the beast.
The kings of the earth set themselves, and the rulers take counsel together, against the LORD, and against his anointed, Let us break their bands asunder, and cast away their cords from us.
He that sitteth in the heavens shall laugh: