Although in one sense you are correct, this is not going to be the actual situation. As a shareholder I would be very angry if my $1500 in value was not available to me between the two dates because I had to wait for the dividend shares to be issued. I am confident that my broker has some sort of trick that keeps my whole $1500 continuously available. Something like "broker-backed promissory shares" will be added to my account on the first date.
Hmmm, I think broker would have to decide this, if it's important to them to keep you happy, which means they have to give you 4x 'ghost' shares for that week, i.e. they have to borrow them from someone else. I imagine this would be done by request only, as otherwise they can't borrow enough shares for everyone on their account.
If you are correct they'll do this, the same way broker can save shorts. Basically send message to anyone that lent shares that by default their newly received 4x dividend shares will be lent out immediately on the Aug 31st. And if they don't want that to happen, contact them... It could be they'll do both, to help their clients. And hence water down the whole event, i.e. squeeze, should they all do that...
It could be also that behaviour depends on the broker, so that we see different treatment of this same situation. I.e. formally, dividends have to be paid, and you don't have access to 4/5 of your capital for a week; yet broker bridges both of these situations for their clients. I don't know if their contracts allow them to establish behaviour they want in this way...
Oh, btw, after some experience with brokerages, I honestly don't think they'd care that you got upset. Announcement is giving you enough information to act before, or after that week the best way it suits you. So onus is on you to deal with the situation. And Tesla gave you notice, and Musk doesn't care about short term stock holders, he's showed that many times, and I have scares to prove it.
