Foil tape is not a good idea inside and should only be used OUTside the enclosure. The only tape that should ever come near the inside of an enclosure would be painters or artists tapes...since they're so weak. And then ONLY when you've exhausted all other ways to keep things in place.

The two best ways to secure the probe are suction cups and hide weight. Those little suction cups from crafts departments with the little hooks work wonders when you bend the hook around the wire. That way the sharp end of the hook is out of the way as well.
If the bottom of your enclosure just won't take the cups, then just place the hide over the wire. Granted, you might have to be repositioning the probe depending on how much your snake likes to 'redecorate'... but that's a ton better then having a snake stuck to tape.