I've had some shaving cream ooze out of the nozzle before whilst the can was in a checked bag, but never have had the worry that the can might burst or the like. It was in my shaving kit along with things like shampoo, etc., so there wasn't any real mess.

A baggie, as suggested by others, should be all you'd need to protect your clothes, etc. Of course, if the plastic plug in the bottom of the can came completely out, you might still end up with more of a mess than the bag can contain, but that's a fairly remote chance, I'd think.