There's nothing difficult about doing it the already established way and I'm not recommending anything else. But when someone already has an UTH stuck in place I don't see any reason to tell them they have to peel it up and risk damage just to put the probe under it. The amount of liquid from a ball python will not cause damaging heat fluctuations. The probe is securely held in place.
I don't know why people seem to think experience has anything to do with this. I have had reptiles including ball pythons a little over 10 years but have recently changed things up a bit. This is the first time I've had a probe set up like this but it's simply not as dangerous as many of you say.
You can have the probe inside. Under the right circumstances, as I've said. That's all I've said. Not saying it's better, but it's an option if you want to take the precautions I have.