I feel that between game actions have two paths.
Any between action system consumes a huge amount of staff time and distracts from the actual game that is ran over the weekend.
Blades in the dark downtime.
Unpaid
Honestly my prefrence. In many ways people already do this by doing adhoc roleplay in whatever manner they can manage. If this is included in your POLAR membership it would occur more often and may overwelm your staff.
Paid Actions
further segments low income players from the rest of the pack
I am really convinced that it is mostly that the “work” is fun. So let’s get paid for do fun work!
If the plan is to make money doing this rather than simply covering costs. I’d be curious how much money is being thought would be made. You would need to stop doing this sort of thing for free for your friends if you charge for it.