Not gp, but I (almost) never read commit messages. And usually tickets are so amorphous that it's hard to come up with a good name for the branch,so I always use the ticket number.
Of course, I have no problem with well named branches, but when not doing it by ticket number, you tend to get nearly meaningless branch names: search, fix_color, tooltip, search2.
That said I'd never mandate it, it just seems easier.
But now the development is pretty much tied forever to the issue tracker. As to read the code history need to have the access to the issue tracker to understand the reasoning. Which to me sounds like a bad idea for the future.
