I don't know if eBay's rule is about Fee Avoidance, I know there was a long history of bidder complaints about the seller not having the particular item a bidder wanted, as well as lots of complaints from people who thought they were getting all three as shown in the picture, and didn't see the words "your choice of one of the three", etc.

eBay decided that the complaints and misunderstandings weren't worth the small benefit "choice" auctions bring to users.