The Mark of the Beast

Having just seen another (presumably hoax) story about mandatory microchipping being on the horizon, I started pondering...

And it was given him to give life to the image of the beast, and that the image of the beast should speak; and should cause, that whosoever will not adore the image of the beast, should be slain.
And he shall make all, both little and great, rich and poor, freemen and bondmen, to have a character in their right hand, or on their foreheads. And that no man might buy or sell, but he that hath the character, or the name of the beast, or the number of his name
- Apocalypse 13: 15-17

Fr Charles Arminjon refers to this passage in his book, The End of the Present World and the Mysteries of the Future Life (available online here):

Again, St. John speaks of a strange, mysterious character which all, "both little and great, rich and poor, freemen and bondmen," will be obliged to have on their right hand or on the forehead; this mark will be a sign of apostasy, attesting that all those who bear it, whether to please the master, or to escape his wrath, have renounced the true Christ, and enlisted for ever under the banner of His enemy.

Now, it takes just one unrepented mortal sin to go to Hell.

For a mortal sin to be committed there need to be three conditions met:

1. Grave matter
2. Full knowledge
3. Deliberate consent

Yet, if everyone is obliged to bear this mark of apostasy, there is surely no real consent. But they are enlisted forever under the banner of Christ's enemy.

However, while there is life there is opportunity for repentance, so can anyone who bears this mark repent of it? Or is the character imprinted as indelible as that of Baptism? Presumably they can co-exist in a soul. I would have thought that Baptism, being of God, was stronger than the devil's effort.

Anyway, a quick google shows I'm not the first to raise this issue! Is there an authoritative answer anywhere out there though?