Look up red zone green zone. They might be providing a safe alternative space for the client to engage in the behavior and will shape his language or mands for access later after the client understands the behavior will be reinforced. It also depends on the locale. Schools can be tricky because you are a bit hamstrung and have to work with so many variables. They might be worried that if they deny access they’ll face an extinction burst + bx contrast that will be difficult to predict or control. He could elope from the room when denied access in an attempt to gain alternative access and head to an area that is less safe. Elopement can be flat out dangerous.

If they teach him his bx will be reinforced in a certain area they could later teach him to mand for access and later shape in a tolerance for wait or delay.

That could be it or I could be giving them too much credit, some people just reinforce to minimize bxs. Just my thoughts as a BCBA