Lost count of the large number of alloy wheels on my cars over the years damaged in this way by rim clip weights. Even when carefully fitted, it's simply a matter of time before these clips cause problems with pressure losses.
One of the 16" OE alloy wheels on my Rover 620ti loses half its pressure in a few days. Got it off and the lead balance weights clipped to the inner rim out of sight had damaged the seal allowing pressure to progressively escape from two locations where the weights were. Here's a close up of the parts involved. If you look closely to the left of the removed weight, you can see a line of bubbles between the alloy rim and tyre bead:
This BAD practice is really annoying and costly. When buying a new tyre I insist on self adhesive weights if needed, not rim clip ones.
......Arrrrrggghhhhh.........
Apart from the already mentioned reason, clip on weights look sh1t too.
) who was doing the fitting had a sandwich in one hand, and was trying to fit me tyres with the other hand 
(this was a reputable shop too) I unpolitely told him to either eat his dinner or fit the damn tyre 
