I'm a bit late to this discussion, but I'll put in my ha'penny worth.
I'd happily go with whatever option you eventually choose, £12 a year (or anything close to that) is a bargain as far as I'm concerned, and I already have CTC and LCC membership, but wouldn't worry if I had to pay another fee on top of that.
A greater issue with that is obviously if charges are seen as being a bar to people joining up, so I think whatever option is gone with, it needs to be one which doesn't dissuade people from coming along to try things out. I suspect charging people £1 to do a ride, and which it's clearly explained is to cover costs alone and that there is no profit element, shouldn't stop anyone joining. If you can't afford £1 for a ride, then you probably can't afford to keep you bike minimally safe either, in which case we probably don't want you along on the ride anyway. Requiring something like £12 for annual membership when people may not know if they want to do any more rides would be a bad thing.
If we ended up being limited to 5 non-members only, as would appear to be one of the problems with the current CTC cover, that could be a problem, since I doubt any ride in 2010 had that few non-CTC members (with the exception of the Dieppe ride, but that was a special case). Whatever way things go, that has to be addressed, or things won't work anywhere near as well.
By the sound of things, I'm probably covered by the CTC when I'm TECing, but it wouldn't have worried me anyway. Simon makes it quite clear that your bike should be serviceable (and as others have pointed out that's your responsibility as a road user anyway). If something fails, then arguably you haven't entirely followed that, although this obviously depends on the exact nature of the failure.
I do my own maintenance, and wouldn't risk my own neck unless I considered myself to be largely competent. I wouldn't repair a bicycle if I didn't consider it safe to ride myself. On the odd occasion when there has been an issue (and the main offending bicycle/rider was mentioned earlier in the thread!) I've made the rider very aware of the risk that they are taking with their cycle operating like that. To an extent people ought to be aware that none of us are partaking in these rides as professional bicycle mechanics, ride leaders etc, and consider that when accepting aid. Everyone has a personal responsibility when taking part in the ride, and arguably that can be extended to them making an assessment over whether they wish to let someone else repair their bicycle. I'll admit that there is also an argument that Simon could be liable since by letting someone like me TEC, he's implying that I have some degree of competence in the TEC task.