well I just did - FYI
Went to the airport with my 75 year old Mother-in-law and went to the customer service counter on the outside in front of where the passengers enter the terminal to leave Bali.
Explained that I wanted to help my M-in-L leave and he said I had to leave ID with him - had bought my passport (even though we don't fly out till later in the week) and left that with him and he gave me a plastic security tag in exchange (about double the size of your passport - yellow). I was waved through by all security guards without question and able to help M-in-L check in and go up to counter where you pay the Rp 150 000 departure tax.
Far happier knowing that she's in the departure area and safely on her way.
Cost me nothing handed the pass back at the counter and was given back my passport.
Great system - that works..............