Dude.. the subject is thermoMETER not thermoSTAT. It's very safe and recommended to put the thermometer probe AND unit inside the enclosure, so you can measure ambient temps, as well as the floor temps on the warm side, and the humidity.

Thermostats control the heat pad's temperature in case of electrical spikes or failure. The probe for the tstat shouldn't be in the enclosure anyway, but won't electrocute the snake if water is spilled on it.