I told them to create an account for themselves so that they can receive the funds directly if they are lucky enough to be picked. Honestly, I don't want to be the middle person since I wanted them to interact directly, and have a personal experience of how things work. Whether they will be able to submit their work or not, is out of my concern, I already have given them the links and instructions so it is up to them to be responsible.
It's good if you have encouraged them to register on the forum and submit their artwork but also told them to have Roobet account also with bitcoin address to withdraw funds in case they win.There have been past instances where members have presented artwork on others behalf like relatives or friends which is why I said there is no problem in that case but you have already told them to directly submit it which is good to go.