Bath tub overflow

Do any of you routinely inspect the bath tub overflow plumbing by overfilling the bath tub so water drains into the overflow pipe? I recently had a client tell me that water from the upstairs bath tub overflow pipe leaked into the downstairs ceiling when her kids overfilled the tub.

Every inspection. We also check to make sure the plug has been removed from the overflow. Found one today that has been plugged since 2001.

although i dont beleive that this be part of an inspection, sometimes the gasket on the back side of the tub (behind the overflow) can be bad, not tight , possibly installed improperly (up side down) by a DIYer