Airbag light

I was driving along steadily when I had a beep from somewhere. The red seatbelt light on the dash display came on and a message saying "check airbag, see handbook" came up.

I hadn't noticed that Heather had her feet on the airbag so she got a quick lecture on how dangerous this was and about a minute after putting her feet back where they belong the error cleared itself.

I have just stopped for lunch and have read the (Fiat) handbook but can't find anything about checking the airbag.

I am going to assume it was a spurious error, possibly triggered by feet pressurising the system a little.

Has anyone else had this? Does the Pug handbook have any more information?

I have seen reports on Facebook of legs badly damaged from the airbag. Obviously being Facebook the reports may not be true and sitting that way without the airbag will probably result in nasty injuries anyway but I consider it safer to not do it.