Tesla used to require you to leave a refundable deposit of $100 in order to reserve one of their vehicles, although even earlier the company required a $1,000 reservation fee (that was also refundable).
Then, in late 2019, the deposit (which counts towards the purchase of the vehicle) was made non-refundable and the reservation fee was eliminated, while now, during the recent AI Day event, the manufacturer increased it to $250 and kept it non-refundable.
We don’t really know why the manufacturer made this change, because Tesla hasn’t released any official statements about the change. Perhaps it was thought up as a means to discourage those who were not serious about purchasing a new Tesla. Losing $250 versus $100 may be enough of a difference to deter those who just put down the deposit, but never really intend to follow through with full payment and have no desire to actually buy the car.
Another explanation would be that Tesla is looking to deter speculators who want to skew the market by lengthening delivery times. They will order vehicles, hold on to their orders, but never follow through with payment in order to increase the time it takes for the manufacturer to deliver vehicles.
This change applies to all models on offer, except for the Cybertruck, which has been delayed until 2022. It seems that the deposit for the Cybertruck is still $100 and is still fully-refundable, and Tesla has now reportedly racked up over 1.25-million order for the upcoming electric pickup truck, so if you multiply that by $100, you can estimate roughly how much the manufacturer has made solely from pre-ordering it.