Airbag light after rear brake work on Boxster

I just had my rear brake discs, sensors & pads replaced and when I went to pick up the car the airbag light was on. Mechanic stated I probably just need knew seat belt buckles. So I was in the process of ordering them when I read of someone else having work done on their car and it turned out something was done with the keys in the ignition which triggered the warning. So I'm speculating if that was the case here. Anyone have any insight or was this purely a coincidence? I also read I need a Durametric to reset the indicator. So I take it disconnecting the battery for 10 minutes will not do it?

Correct, battery disco will not reset. Need durametric or PSTII or PIWIS to reset. It will tell you what tripped it anyway too which is helpful. My guess is battery disco w key in ignition as some shops will do that to prevent tripping ABS sensors when pushing calipers back in to create space for new pads.