If they go this route than it will only lead to them cancelling it all together months later due to lack of buying interest.
Only logic that makes any sense to me is if this is purely done at request of many sales reps complaining about customers asking for the Stealth all the time and those customers choosing to wait for one later rather than order now.
Bingo, to both of those, in my opinion. They likely made the "stealths" as an insider type thing.. gorilla marketing style. Then, because "nothing" good stays underground for very long, AND because, of all car buying demographics, the "tesla buying" demographic is decidedly onlline, forum connected, fairly tech savvy, etc, it got out. It got WAY out, and then people all over the country were bugging sales reps asking (and asking and asking) for them.
All those calls (and response to calls, and time hunting these down, emailing up the chain to manufacturing, etc) cost money. They dont WANT to sell the "stealths". They will sell you one if you really want one, but not to save you money. You REALLY "dont want" the PUP items, then you dont have to take them. People say they dont want them, but they absolutely will take them if its the same money either way. Most will (a few who really want to put other items on the car than tesla provides may not take them, but that will be rare).
So, "they dont want to sell it, so can cancel them due to lack of interest" and "they were being bugged about it all the time, AND people were holding off making purchases to try to get these instead of just ordering". Take away the money incentive, and this goes away.
What I could see them doing at some point is giving a small discount on the model 3p without performance pack (aka stealth). Something like 1k less for not having the performance pack items or something. In the meantime, they want people to just order the full performance and stop waiting for the cheaper stealth. This is one way to do it.