Helping 2yo deal with violence from other children

[BookTart]

DD is 2.9, and a very bright, funny, and physically capable girl. She loves climbing frames and soft play, and recently we've had a couple of situations where older/bigger children have behaved violently enough towards her that we and the friends we were with have had to leave. She is quite small (0.4th centile), which may be relevant. She also likes to approach children she doesn't know so that they can be "friends", which may not always be appreciated I guess.

The first time this happened, two boys in a playground followed her around the climbing frame, hitting her whenever they were out of sight. The second incident happened at soft play a week ago, when a school-aged girl (so maybe 5?) punched her and pushed her down the slide from the top of the big frame. In both cases she didn't hit back, and she isn't given to hitting/biting/scratching in general.

This last event seems to have upset her very badly, and she has become very clingy. She doesn't want to go to nursery in case the "bad girl" is there, and she talks about this girl unprompted several times a day. She is also now asking not to see a friend that she has played with weekly for well over a year, because he also shoves/hits her occasionally, although this behaviour feels much more on the standard end of the toddler spectrum to me.

I'm obviously aware that small children do hit each other, but what do you say when things are a bit less 'usual'? We left the place each time straight away, I've tried to explain that it is very rare but that some people are just mean sometimes for no reason, I've told her that she'll never see these children again, and she is still very upset. I have no personal experience of this from childhood to draw on, so could really do with some sage advice from the MN collective. She is so lovely and kind, and I hate the thought that she's already having to deal with things like this.