if you have a very good reason and a very NICE check-in agent, you may be able to get a gate pass:

1. in 2006 Dropping my fiance off at IAD when severe storms were forecast - checkin agent gave me a pass to accompany her so that she would not be alone in case the flight was delayed or cancelled - agent volunteered to do this - I did not ask as it didnt occur to me it would be possible.

2. within the 6 months I have used this: when passengers have physical disabilities they will often give a pass. This works best when the PNR notes that the pax needs assistance. But it has also worked for me just by asking saying "my grandmother is flying and really would like someone with her/meet her." You can explain the pax is not necessarily disabled, but is just old, not confident, scared of flying, etc. If you look honest and are sincere, it will probably work.

of course, in these situations you would not be able to bring anyone else with you.

and, of course, it all depends on which agent you ask.............