It also sucks if you want to reuse your thermostat for another enclosure in the future because I'm not sure if the heat has any effect on the bonding of the glue to the probe itself. You will be able to remove it from the glass but I'm not 100% about removing it from the probe. For that matter, I'm not sure if the heat produced by the hot glue could effect the probe itself. I'm not saying that this is the case - but I don't know, it would be something that I would be worried about (but than again I'm a little paranoid).
Cheers