Is someone alerted if you check their location? Or is it anonymous?

I am wondering if I can look at someone’s location, using their Gmail address anonymously?

I cannot attach a picture in this sub, but I’ll try to explain my quandary/question.

I open Google Maps app on my iPhone. I click on my profile right upper corner I click on “Location Sharing” I can see some Gmail contacts that I presume are sharing their location- these folks have the little Google Maps upside down year drop icon on their little profile pictures.

Can I click on those users who have that icon and see where they are without them being notified?

Or- do you have to get permission to see their location?

Or are they notified if you look at their location?

I hope these questions make some sort of sense!

Thank you.