Stopped by the park (just swings & a slide) with DD (nearly 2) for 5 mins on our way home from nursery as she wanted to go on the slide.
2 older girls, I would guess around 9 or 10 were sitting on the slide - one at the bottom, one half way up, so not sliding, just sitting eating sweets.
DD ran up and I asked if it was ok if she had a turn. They said yes and got up - one sat on a nearby bench.
DD started to climb up the slide and the other girl climbed up RIGHT behind her, literally one step behind her the whole way. DD slid down and came back round for another go. The girl did the same thing again. The third time she did it, DD was visibly agitated by how close she was, so I said "could you give her a bit of room, she's only 2
' very politely.
Girl looked pissed off and stormed off to whisper about me to her friend on the bench 
DD had a couple more slides then we left.
I don't quite understand why she was so annoyed with me - I didn't tell her to stop playing on the slide, DD was taking turns, not hogging it, I was not mean to her.
WIBU and missing some commonly known park etiquette?
Not an issue that I will lose sleep over, just curious.