I am coding an online experiment for groups of players, and I am grateful for the sample projects in otree-snippets which are using group_by_arrival_time, in particular the ones which are implementing fallback tasks for players who have been waiting to be matched for a period of time.

Is there any way to tell if a player has been on a GBAT page for >N seconds because they went inactive by unfocusing their tab (and therefore hasn't been included in waiting_players) vs a player who has been there >N seconds and had the window focused the whole time and just can't find a partner?  Ideally we want to pay the latter but not the former.  

A player could be inactive on the page, and then when they come back they're suddenly included in waiting_players again and their calculated waiting length will be very long.  Has anybody else dealt with this?

Thanks,
--Chris