I'm sure that a lot of people do feed F/T, but I think that only a small minority of those in that group will refuse to buy a snake because it is not on F/T. It certainly isn't worth feeding an entire collection F/T if you breed your own rodents just because you might miss a sale or two. I've found that it isn't that difficult to switch from P/K to F/T (I occasionally run out of appropriate size rats) so I'm not sure why that is even a concern.