Since I don't bag anything I never use snap on totes for snakes.
There are a lot of good (secure) boxes out there. Some look like tool boxes. Some seem like foot lockers. Regardless of the manufactures intent they make excellent snake transport boxes.
They have latches and most are capable of being padlocked.
If you're concerned about how snake proof the box is put a 12-14 foot retic in there. If he can't escape, nothing can. D.C.