I have seen this question so often over the years and there are two mixed thoughts;
First a well known sub male in the mid Atlantic is kept in a CB-6000, could he pull out? Yes but he sees it like this, she locked it on, he better not sneak out. It's a matter of honor and dedication to him.
Second - and this is in line with Ms. Lori and her chastity devices - I have the same opinion on bondage, why tie someone up if they can easily escape? To that tune, get a Prince Albert piercing and a Lori device. Once that pin is locked in place, you won't think of pulling out, it is done and over with right then and there. Her devices are custom fit, well made and yes, expensive but if your desire is high security, then a Lori or equal is the way to go.