Flower is typically tested for compliance against the psychoactive delta9-THC in most states (not in all states though), which ignores the THCA content. But THCA is converted to delta9-THC when heated/"decarboxylated", which is a pretty big loophole.
These communities [1][2] are buying ounces of weed through the mail.
A better example is probably this 17 gram edible [3]. At 0.3% d9-THC, that's a ~5mg dose of psychoactive THC per package. You can buy these all over the US in states like Texas, Oklahoma, Alabama, Mississippi, and Kentucky... Places not exactly known to be "weed friendly". See this map [4].
Pot has basically been legalized everywhere and people just don't know about it yet.
[1]: https://www.reddit.com/r/hempflowers/
[2]: https://www.reddit.com/r/CBDhempBuds/
[3]: https://lunchboxalchemycbd.com/products/full-spectrum-hemp-s...