Thanks, tillypeg and Mark.
One tree owner seems to be a relative of a deceased American cousin of mine whom I never knew. Our mothers used to write to each other. My aunt in America died years before I was born. She was eldest step-sister of a large family. The cousin was born in U.S.A. in 1918. Her younger brother served in WW2. I filched 2 photos of my aunt from the tree since I'd never seen a picture of her before, plus one of Grandma. I don't know the protocol regarding photos. I tried to write a message about one picture but wasn't able to because I was on free access. I put up a tree for that side of my family. If my American cousin's relative receives hints from it and takes time to look at it he should realise it's the same family. I added sources that I didn't find on Ancestry!