Following on from my other "issue" posting (#2), perhaps even as alternative, I've had an idea for temporarily disabling blocking for specific sites. Then you wouldn't even need a list and neither would you have to revisit a site to enable blocking again. Would that be a feasible feature to request?
That should also be possible and I think both recommendations will be implemented.
I'm not sure how difficult it is to store data only for the current session in Firefox addons but I'll likely find a solution for this.
Should be implemented with the next version,too.