Actually i've reserved many things for online pickup from Walmart.com and the price online is usually different from what is in the store. By your logic, i should pay the in store price that everyone else is paying that day and not the online price i got yesterday.
I think typically, Walmart and other retailers do typically allow you to pay the lower of the 2 prices, I know for sure that Walmart does. They may not automatically discount, but they will upon request. Hell, if you order online and pick up at Lowes, and the price is lower, they give you an extra 10% of the difference to make sure you're "always getting the best price" (you do have to request the price match, but when you do, its 110% of the difference they take off your bill).
You don't have to be happy, that's just the reality of the situation. Think of ALL the people who didn't order the PUP, should they now be forced to buy a car with PUP since that is whats for sale today and pay the extra $3k? If your answer is no, then you're a hypocrite.
If your answer is yes, then well sure Tesla should honor today's price.
Well, no. If they don't get PUP when they ordered without it, thats fair. If Tesla runs out of the non-PUP parts and decides to just upgrade them for free, they're lucky and get the best deal (and there is the possibility someone literally does not want the PUP even if it was free)
Its not being a hypocrite, its good customer service. The only places that don't really typically do this are other dealerships, house sales (since every one is literally different and property values change sometimes just being a few lots over, so that one kind of makes sense), and places where there is no customer service at all, like eBay auctions (even most of eBay's new, unopened items will price match competitors with 110% of the difference).
Obviously the cut off point is a point of contention that varies between stores (some do it for the entire return period, like Best Buy, some do it until its received by you, some only give you 48 hours after ordering, etc)