I figured that if I buy a $7 upgrade now, at least I am guaranteed to get in with a GA membership and now you get a T Shirt and get to choose the size (maybe).
It seems a bit random what seats are available, so no one can guarantee what will be the best available. But if you don't want to end up with a bunch of poos and wees, I was happy to get a ticket in a designated EFC area, albeit L4.
Many will probably abandon their seats if better GA unallocated seats are available. But this will lead to some GA anarchy no doubt.