I think it depends alot on the family?
For example, my parents and his parents let us do whatever we
wanted, and how we wanted it because both parties agree that it is
"Our Wedding", not theirs or anyone's else. (For the record, we
didn't go to them to say it's our wedding, but their advice when we
said we are getting married)
The most important thing is that we are happy, and that if we
needed help in anyway, just ask.
I know alot of more traditional families expect alot from their
kids, that it seems pretty much like their own wedding. I guess
that is concern shown in another way. However, they forget by doing
so, they cause unnecessary stress for the couple as well.