Well, common sense dictates that she is going to want you for a Visa, but then again, you need to ask yourself why you've chosen this route to find a wife.
More than likely, if you do choose to go this route, it's because it's much easier to find someone aesthetically appealing this way, rather than the conventional way, in America. In the U.S., fat single mothers are in huge supply. Unless you are very wealthy, and or very good looking, the attractive girls are very difficult to settle down with.
The Russian girl is going to realize this as well, so as long as neither side isn't completely deluded or lacking in common sense, this can be a much more honest relationship than the typical American marriage, that has a 50+% divorce rate anyways.
According to the INS, only 20% of these arranged type of marriages end in divorce.
I look at it the same way as I view prostitution. I know she's in it for the money. She knows I'm in it for the sex. It's an honest transaction.
I'm very much in favor of legalizing it, since at least that way, taxes aren't evaded, which is the main reason LE feels the need to entrap people anyways.