My friend and her DP went away for the weekend and her DS came to stay. He 11 so is a bit younger than my DS but they are friends, but don't see much of each other.
I thought the weekend went well for all the children.
She has just called me to say "what was wrong with your DS's ?"
Her son had been 'VERY unhappy and hurt' that my youngest DS had gone off a couple of times and played on his laptop rather than playing all the time with her DS.
I did see this, but as my older DS stepped in to the breach so to speak, I did not think it's a big deal as i know my youngest does need time on his own and does take himself off for this anyway. There was no fighting or unpleasantness.
I felt very defensive and felt like she was trying to extract an apology for me. I do not think my DS's behaviour was rude or unkind. I did apologise to her though but feel like i had actually nothing to apologise for. 
I feel it was unnecessary to mention this to me and feel a bit upset with her. I feel like she was judging my hospitality and that of my DS's.
I feel like saying 'no' next time she asks me to look after her DS.