Initially I was against it. I wanted people to learn from my map, and I wanted to encourage more of the same sort of work from other people.
Unfortunately, I've ended up not altogether happy with some of the changes that have been made. People will add stuff you're not happy with. They might not playtest like you do, and they might not balance like you do. There's a version of my mod out there now with tooltips missing and god knows what else. Another class has been added to it, being an RPG mod, and from what I've heard he's way, way overpowered.
People can also use the open map to cheat too. Chuck in a few triggers, fire up the game, a command here, a command there... insta-high level character. Get the save code, quit, fire up an online game, and you're playing with a character you created in about 30 seconds. That's not right.
Nah, if people want to learn from your map, they can easily email you asking for an unprotected version. This is the way I'll be doing it from now on...