Furthermore, setting up such things is not cost-free, and if the high-volatility situation is temporary (which is very likely) it could well be that it isn't worth the cost, complexity and risk.
"It is illegal to pay directly for general transactions with dollars or Euros."
Nonsense. The surcharge is the difference between the spot rate and the futures rate with which they hedge. They can easily predict (to a reasonable degree) the volume they need to hedge by estimating their market.
The derivatives market still exists and you can null out future FX risk by paying whatever the derivatives market is charging for it now and passing that cost onto consumers.
Basically, you make the customer buy insurance against the ruble losing value against the dollar. It's like charging a subprime borrower PMI.
My guess is that your typo isn't too far from the truth. Everything we've seen lately with regard to falling oil prices is geared towards attacking the Putin regime. Eventually the Russian people will find themselves living in a North Korean-style pariah state... or else they'll wake up and take drastic action to keep that from happening. Either way the medium-term outlook for the ruble is pretty much toast.
Amex disallows on their network but Visa and Mastercard do not. Unfortunately, Amex also has forex fees on most of their cards.
bloomberg.com/news/2014-10-16/saudi-arabia-oil-stance-seen-targeting-opec-output-discipline.html
wsj.com/articles/saudi-oil-price-cut-upends-market-1415063053