score:6
Here's what I've seen in my (extensive) Russian travels - please take with a grain of salt, this is obviously not the official position:
The entire "voucher / tourist confirmation" system is a bit anachronistic now, a vestige of the Soviet days when there was tight control on what foreign tourists were and weren't allowed to see in the country. No one takes it seriously anymore (unless you are visiting "closed" cities or those close to border areas, in which case it is a different approval system anyways). Yes, formally speaking it is a requirement, but normally independent tourists would just get this from a service company (e.g http://www.visatorussia.com/ or http://realrussia.co.uk/ or http://waytorussia.net/ ), and it really doesn't matter what hotel is listed there - it's never checked - not when you enter Russia, and not when you actually register at your real hotel. It's just a way to extract a little bit of extra revenue from foreign tourists.
I am guessing that realistically, the only time vouchers would be arranged through your actual hotel is for things like business meetings and conferences where your host in Russia will do the legwork to arrange it with the hotel.
By the way, don't expect credit card data to be treated in Russia with the reverence you're used to. Even if you find a secure way to transport the data to the hotel, remember that you have no control on how they treat your data afterwards.
Remember also that many tourists in Russia successfully stay in small hotels/hostels that don't issue vouchers, private residences/CouchSurfing, camping, etc. - all this despite having a different hotel listed on their voucher.