A lot of mosses get surprisingly bushy, too. I still wouldn't do it.
Obviously, you aren't going to get a lot of support for this idea around here. I'm not scolding you about this. There's enough boy in me to see the appeal in gluing tiny decorations to a mystery snail. Those little hermit crabs with tiny anemones growing on their shells are adorable. But the difference, of course, is they can shed their shells whenever they decide to. Snails can't.
So, despite the coolness factor, I wouldn't glue, oh, a little jockey, or a tank turret, or a pair of viking horns, or a fake mohawk on a snail shell. (Those are stupid, tasteless examples; I'm being ridiculous on purpose) I can see the pokeymon-ish appeal. But I wouldn't, and I don't think you should, even though what you propose is much nicer than any of that. What you want to do isn't like putting a cute little bandana or a sweater on a dog. Super-gluing a decoration on a snail's back is permanent. When that plant dies or breaks off, it's going to leave a scar, and it might even damage the snails shell. Maybe it won't. Is the coolness worth the risk and probable discomfort to a living animal? To me, to a lot of people, it just isn't a good idea.
[Edited far too many times in an effort to think this through and articulate why this strikes me as a bad idea]
