OK cannot speak for the USA but in UK it is only legal to go above 400' if FPV with a spotter, non commercial and in non controlled airspace. So it is technically possible to do legally but I would personally be cautious of advising such to somebody on post No. 1
That’s why I specifically stated U.S. Nor did I give legal advice, instead recommending people read and understand the law as it is written. I bear no responsibility for people that choose to be lazy or fail to perform their due diligence. We should not fear the law and making full use of what is available to us is totally reasonable. We each only need to accept and exercise the personal responsibility expected of us to review public domain government documentation and therefore know the truth. Contrary to popular belief, everything we read on the internet is not true.