I recently got into the hobby of native beetles and as I produced large amounts of flake soil I came into contact with tons of people working with crazy beetles, and after talking to them I came to a few conclusions:
1. The process of illegal imports is a much bigger deal than the keeping of the species itself. There are tons of people that keep them in the US apparently, and some of them are pretty open about it. Godshobby was selling rainbow stags on ebay for quite a while, and Underground reptiles even was selling exotic phasmids. Furthermore a lot of US keepers started their collections buying exotic beetles at reptile shows.
2. None of the foreign sellers offer any sort of quality guarantee or live arrival, because it is not feasible, and because of the hibernation of beetles, importing beetles often leads to drastically shorter life spans. I have not raised my chrysina yet, but from what I hear, many beetles have a hibernation phase where they should not be handled before they become active and eating. Foreign sellers that are exporting illegally will ship beetles in this state when they shouldnt be messed with because they do not make noise. Making noise in the box is a checkmate for getting packages seized. Obviously tossing and tumbling in the boxes does nothing great for them. As for grubs I would imagine the long transit time would also affect their health.
3. Because you are engaging in illegal activity and these sellers are abroad, they can easily screw you and you would be able to do nothing about it unless you want your crimes to be exposed as well. I have heard multiple horror stories of getting the wrong beetles without any warning or even recieving grubs that morph into a cheaper species of beetle months down the line.
Ultimately, illegal imports are something I would never recommend to anyone, but if you manage to find a REPUTABLE US seller that breeds him or herself instead of importing and flipping, you would be part of a relatively large group including those that have kept for over 10+ years and post about it on facebook groups openly. That being said I would imagine part of why they are so open with me is because I have been integrated into the reptile hobby for quite a while now and do not get involved in drama and also do not share their identifying info without their consent.