Burnt snails

I have noticed recently that my turbo snails pretty much get everywhere on the tank walls in their search for brown algae. That includes crawling on my heater. I have yet to see one make it past the insulated top of the heater, but the heated part is clean as a whistle, and it used to be covered by algae.

What happend if the heater cuts on while a snail is touching it? Does it fry the snail? Has anyone seen this happen? Obviously a snail has made it across the heated part before to clean it.