On many cars the culprit can be the connections under the front seats (the airbag has to know whether the seat's occupied, I think the connection's for a sensor, IIRC). With the seat being moved back and forth the connection can come loose, and trip the warning. That's the first place I'd look.
The general advice on my previous car's forum was at least to bind the connections with cable ties, but preferably to bin the connector, and solder the joins.
HTH
Malcolm