Jerome,
As you may remember, I tried to get the AWOCoupon to work but it couldn't meet our needs and that was one thing that it couldn't do. I do not want to go through another application like Community Builder as I have done one site with it and, while it is great, it is just too much for what we need. I think I'll just see what I can actually develop myself or have the client to simply mark in her calendar to manually remove them from their ACL group while I look for a better solution.
Just thinking 'out loud' but I'm wondering if I could create a plugin that could be run daily via a cron job to check coupons for expiration dates. When it finds a coupon who's expiration date has passed, then find the order that the coupon was used, see the product that was purchased (there are only two) and based on that, then find the customer record in the ACL table with the pertinent ACL group and delete it. That sound's logical to me. Does it sound like a good routine to you?