Non-jokingly, an owner/friend who decided he's going to wait until autumn to replace his S said if I could use his config invite (he's had it for like a month now) and he could use mine when the time comes without Tesla throwing a fit, I was welcome, but it'd have to be seamless. Tried to get any sort of confirmation from Tesla that it'd be allowed for him to punch in my details and my driver license, insurance etc and have me take delivery directly and preserve the tax credit, but the various people we talked to were pretty adamant it has to be direct family. My suspicion is that if we'd just done it and showed up and insisted, they'd have done it, but I'm not going to strongarm someone into trying it and I wasn't going to lie to Tesla and say I was family either. Thus, I continue to wait.