Charming

Beanie confirmed to me that the barrier invisible but I now have a follow up question. What happened if someone, for example a students tries to walk through the barrier either knowingly or unknowingly? Is there an immediate feedback like they get smacked back into the grounds or is it an alarm that tells the headmaster that something is amiss?

Thanks

They would not get smacked back onto the grounds but also wouldn't be able to walk forwards; like walking into a glass door. (It's also worth noting that the barrier is fairly far from places that students would usually go.)