With a regular (3/8) drill, I've had the problem with cracking on occasion, but not with a Dremel and the small (1/16", I think) bit that comes with the rotary tool kit. Of course, there's always the possibility of accidental burn when melting holes, and I hate the smell and "strings" of melted plastic that stick around after. For my own part, I found it messy and awkward.
And I've never had the problem with snakes hurting themselves on holes. The newborns can't even get their snouts into these, even if they really wanted to. Just my experience...I try not to be afraid of trying something different, whatever the perceived "preferred method" may be. But of course, everyone has their own favorite way, this just happens to be mine.
As you can see in the photo, the holes are really smooth. I actually went a little over-the-top on these tubs and really tried to err on the side super-ventilated. This "pegboard" look is great for Desert Ratsnakes, but I'd go with less holes and more towards the top on a corn, especially if you live in a dry climate like me. If you live in a humid climate, go with more holes. And if put a humidity box in your tubs (not matter where you live), go ahead and drill the heck out of 'em! 
DR

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