I don't think I was bring unreasonable here, but happy to be told otherwise...
Took DS to the playground this morning. As I arrived, I spotted a personal trainer and his client working out in the soft sand area. I looked around and couldn't see a buggy nearby, so it wasn't a new mum trying to get back in shape. He had left a kettle bell lying around right by the entrance to the park where it could easily be tripped over.
I watched crossly for a while, until they got one of those plastic sports skipping ropes out - those things whip through the air and could have really hurt a child if it caught them. I figured enough's enough, so went over and asked them to leave. The trainer got very defensive, said he uses the playground a few times a week and no-one else has ever complained. He likes the soft rubber flooring and using some of the kids play equipment for his sessions. He then said he wasn't endangering any children (he shut up when I pointed out the kettle bell lying around) and that the other mums there at the time didn't mind. Eventually, they left.
Was I right, or being precious? The playground is in the middle of a big common, which even has another area with free outdoor gym equipment. Surely it's inappropriate to have heavy weights lying around where toddlers are running riot? However he's right that the other mums had just been ignoring him.