Then I stand corrected, when we went to our SC last month (Dedham MA) they didn't have a Model X to test drive...we were told we would have to schedule one online and then they would contact us when one became available. After not hearing back for a week I was told the same thing, and as of the other day I just gave up calling and will just stop by the next time I'm in the area.
The bottom line is that unlike other dealerships, Tesla doesn't always have loaners or vehicles to test drive and that has been shown here time and again (think Uber credits vs. Musk's promise of "you'll get a Performance model as a loaner!"
Tesla Model S Loaners For Tesla Model S Owners, Elon Musk Says
I get the issue, but for someone that randomly walks in hoping to take one for a spin, that's not always the truth unfortunately and varies by location tbh.