Online, I mostly buy from established dealers. I'm sure I'm paying more overall than if I were buying from hobbyists, but my experience unfortunately has been that I can't trust any particular individual random person to 1) show honest photos, 2) sell clean livestock without undisclosed risks, 3) pack properly, 4) ship properly, 5) communicate well, and 6) have a dead-or-dying-on-arrival policy that is fair.
I however do agree that it is on the buyer to know each seller's 'rules' and decide for themselves whether they're reasonable or not, and if not, don't do business with them. But new hobbyists may not even realize that such tight restrictions exist. It isn't obvious that someone would require a photograph of something dead in the bag within just one hour of arrival. I remember, early on I bought a large Hawkins echinata frag from some guy. He frankly didn't pack all that well imo and the water in the bag was cloudy on arrival. Now of course I would contact him right away. But then, as a new aquarist and not knowing the rules, all I could think of was getting the frag into clean warm water to see if it recovers. Of course when I realized that the frag was completely dead and contacted him later that day about it, past his deadline which at the time I didn't know existed, he was aggressively suspicious that I was trying to cheat him somehow. Just one example of an interaction I don't care to repeat.