Restrain them and remove the painting from the frame. Let them figure out how to detach from the empty frame (while sitting in jail). Using the bathroom should be interesting.
I wish at least once the powers that be would use a solution like this. They’d probably get into trouble, though, if they jailed them like that.
Just turn them out on the street and ignore them. (And take away whatever solvent they brought with them. Let them rely on the kindness of strangers.)