My mother passed away 3 months ago. But I recently found out that some stranger posted a memorial to my mother a year ago. She had her gravestone set up in advance. There was no death date but that didn't stop them. They just put "????" for the death date. Obviously, if they are posting living people as dead, their standards for accuracy are rather slim.
I have contacted them and got no response or apology, although the contributer did immediately remove the bogus memorial. I have however, received an email from a "friend" who is a find a grave contributer, who basically told me to get it removed and move on with life.
I personally think that people need to give the families time to grieve before they go posting information on strangers. To them, the graves are just rocks with words. To us, they are our family members. I just wish they would stop hiding behind the response that they are "preserving their memory so they won't be forgotten." That is MY job not theirs. Go preserve your own family members, and let me preserve the memories of MY loved ones.