Any risk in logging into someone else's account on my PS4?

Long story short, someone asked me if I could log into their PSN account on my console to try and get a trophy for them (the FFIX jump rope trophy, in case anyone is curious). People usually don't ask me for help with anything, so I'm kind of eager to help them out lol. I wanted to know though, is there any risk for me if I do this? Could they somehow remote play once I've signed into their account on my PS4 then make it their primary PS4 or something?

EDIT: I suggested using Shareplay to them but they said their internet connection is really awful, so it wouldn't be a viable option.