If you secured it well, you could make larger holes and cover with window screen mesh (silicone in place or hot glue), the plastic type, to use as ventilation. Tubs tend to hold humidity high anyway, and if the plan is corn snakes that isnt needed.
I've got a high prey drive dog in the house who didn't manage to find him for almost 5 months, so it may not be too bleak if you track an escapee down quickly. Depends how much clutter he has to hide in that cats can't navigate easily. Or it'll tip you off if a cat is digging somewhere weird.
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