My opinion is trying to be over pedantic about the rules will make it not enjoyable to manage or judge, since no one wants to write a book of rules in their free time. If you're doing/getting something that feels like maybe it's not in the spirit of a $200 spend, good natured, friendly competition, then ... don't do it.
The baseline seems like it's imagine you get $200 to spend on a reef tank, and you have nothing to start with (similar to how most of the people in the world getting into the hobby are); what can you pull off?
Freebies or deals on Craigslist/marketplace seem freely in the "build from bootstraps" spirit. Pulling $4k of stuff out of your garage, having your wealthy spouse buy you a CDA peninsula, and picking it up from the factory in a cybertruck with an overnight at a Ritz-Carlton doesn't.
Lots of gray area. Seems like "new" acquisitions as gifts fall closer to out of the spirit.
But I also can't setup one more aquarium, so I can't participate, so my opinion doesn't matter!