I helped my mother with her FB account and someday started to change her birthday every 3 months or so. She started getting "happy birthday!" every three months

I helped my mother with her FB account and someday started to change her birthday every 3 months or so. She started getting "happy birthday!" every three months, usually from the same people. She was initially mad at me (I told her it was my brother who was doing it :)) but then realized that it helped her to identify the senile ones :)