And with a larger snake, they can push against the back of the enclosure with their lower half as an anchor...I could totally see it happening. My large (7') adult Florida
rat snakes are quite pushy in their cages at times...they get restless & maybe they can smell the females at the other end of the house? I don't know, but they're strong.
I'd say locks are a plus if you ever decided to sell the cage too- seems better to have the option. I can't picture a BP sliding the glass open but a BCI? Sure!