I'm definitely open to being wrong on this - in fact, I'd welcome it since it would work out for me. I tried to make it clear that it was my guess.No, it's really not going to be a free-for-all. I'm surprised this idea is persisting despite direct evidence and past precedent to the contrary.
Elon Musk has clearly and unambiguously stated your place in line matters for AWD. This happened just 3 weeks ago, so we know their plans won't have changed since then.
Tim Shelton on Twitter
Elon Musk on Twitter
Configuration with the Model X was truly a bit of a free-for-all. They opened the design studio in blocks, but they were large blocks relative to the number of reservations (about 5000 reservations per week out of ~22k reservations, increasing at the end). If one used the same ratio for Model 3, and note that I'm not saying this is realistic, it would be something like 80k reservations getting design studio access every week. If you're undecided for a week, in would come another 80k reservation holders who could pull the trigger faster than you. With the X, there were open questions and many owners who had reservations for years wound up in line behind the general public.
My point is mostly that we shouldn't expect it to be entirely orderly. With Model X, Tesla was willing to give you approximate access to your spot in line, but you had to be ready to pull the trigger on a vehicle unseen with outstanding questions (hidden charger options, for instance). I foresee similar situations with the Model 3 that could upset certain people if they don't meter their expectations.