@Zoe338< maybe the mother doesn't know how to use or have access to internet.
Do remember we all get older at some stage in our lives and some people have challenges to do day to day activities others take for granted.
It's all very well and good to say it's a 3rd party booking, and yes maybe the daughter could include her mother on her Profile/ account, however with Photo ID verification etc we all know the loopy de loop circle some of us have been through!
The best you can do @Zoe338 is to be civilized and treat your Guest how you would like to be treated.
How for instance would you feel if it was your own mom?