Why can’t you open a file in the trash?

What’s the logic behind not being able to open a file that is in the trash (in the Mac OS)? It hasn’t actually moved. If the OS wanted to, it could open the file. Despite this rule that has existed for as long as I remember, I still try to open items in the trash that couldn’t be deleted because they were "in use" (usually a screen grab or something that I sent via iChat and really isn’t currently in use).

Annoying.