[fwdude]

How much revenue does one raise with a 100% tax?

With a captive audience, a lot.

If Mexican workers want to send $100 to their homeland, they have to spend $200.

[bagman]

I guess we disagree as to what a 100% tax means. Your suggestion that $200 would have to be sent for $100 to get through sounds like a 50% tax to me.