Apart from laziness and lack of interest to learn, the major thing I see there is that most investors just want people they could hold accountable if anything goes wrong. They want who they could blame and hold responsible if they run at loss and that is why some are ready and willing to give whomever is ready to do the investment for them but if you must accept it, you must make them sign an undertaken to accept in fate whatever happens because you just need to let them do that so you would be on the safe side or better still you avoid doing anything for them. You just teach and explain to them how the process works and leave them to run their investments themselves.
If that's so, then it means such persons was never meant to invest in Bitcoin, although there are people like that, they don't want to be responsible for their own actions, they want to rope someone in, in everything, and I think this should also sound as a warning to does who will want to persuade anyone to invest in Bitcoin, what you owe any interested intending investor, is to brush him through, but don't make decisions for him or her, he should be the one to make up his mind to invest or not, in other for you to be exempted from his or her blame whenever, there nothing that'll make me agree to invest for anybody, because people can be very delusional, I won't even buy into signing any agreement as you suggested in case, I got my reasons, so I won't risk it.