While it would appear to be a convenient place then that only lasts until you fall off a bike/skateboard/whatever and end up with sauce all down your trousers and shoes, and possibly some people freaking out if it is red sauce and they think you hurt yourself, or you actually hurt yourself and effectively rub chillies* into the wound.
Similarly sauce in packets in knee side pockets on combat trousers/cargo trousers has a tendency to go pop if you squat. Squatting might be mostly avoidable if you are not a Slav but never the less is an action you might find yourself having to do at some point.
*most restaurants I go to will have a selection of normal sauces else I won't go there, however I and most others long ago gave up on anywhere reliably having a properly tasty but also spicy sauce and thus with the addictive nature of chillies it is one of the popular choices for sauces to carry around.
While I know you mean in case of someone confusing schooling establishment from shooting establishment (many of the same letters) I am still going to read that as lockdown (also known as lock in) for a pub
being drunk in school was either because drunk on playing field or could not be arsed with one particular Thursday afternoon so went and had some beers and played some games instead before returning for an ill advised last lesson/period