DS1 is just turned 19yo has been working full time for almost a year.
When he started work I helped him set up a Homebuyers ISA with a monthly standing orders thinking it was better that he saves something than nothing, the was a possibility of free money and maybe he would eventually leave home
He had a cuppa with my parents (in the garden) last week. My Dad is very into financial planning and security can't think where I got it from and asked DS if he was saving anything.
DS's response was that his mum had "made" him open this account. Dad's lighthearted response was that you're an adult, mum can't make you do anything.
Which I guess is true, but I've realised that actually, even at 19yo he does "do as he's told" quite often. Only sensible precautions or courtesies but if I ask him to clean the bathroom or wash the car (which he uses) or let me know if he's in for dinner he doesn't see that as a choice 
and I don't expect he felt he had a choice about the savings account either