The fact that Tesla is not willing to refund them the $1875 back and is instead saying they have the option of picking up in early Jan or cancelling their order tells me Tesla has a lot of orders on the books to take their spot. Combine this with the fact that there's been zero end of year discounting and that prices were actually raised throughout Q4, and there's pretty strong evidence that Q1 demand is going to just fine.
An important demand indicator for me will be that Tesla will provide no configuration of any Model with unlimited, free Supercharging - also because IMHO Elon Musk was right when he said that unlimited, free supercharging incurs suboptimal behaviour.