It's not a bad idea, and has been suggested by other people, but it would be a lot of work to implement. To do this properly, we would have to look several moves ahead (the way chess programs do) to detect any dead-end moves, ie a sequence of several moves that can be made, but don't progress the game at all. It's a lot easier for humans to recognise when there are no moves left, but it's very difficult for software to do it.

So I'll add it to the TODO list, but it's not likely to be implemented any time soon, as it's a lot of effort for not very much return.