It may not be the most effective punishment, but it probably isn't absolutely wrong to do either. What you're describing (having a child sit out of an activity for a period of time as a consequence for breaking a rule) is a typical punishment, and sounds like a form of "time out" as well, though there is a lot of debate about what "time out" or "effective time out" really is.

Some things that would make it less of an appropriate punishment were if the children were out of sight of supervision, or if the punishment lasted too long (e.g., the entire recess for a small infraction).

Even if you were uncomfortable with a particular punishment used, I'd approach the situation by asking for more information about why that particular punishment was used, and if you strongly disagreed with the punishment then possibly ask about the possibility of a different punishment being used. I probably wouldn't ask for a particular staff member to be removed unless a serious ethical or morality violation had occurred.

A big thing to keep in mind is that you are in a partnership with the school, and the stronger the relationship you have with the school and particular teachers, the better off your child will be. In as many situations as possible, try to work with school staff to promote the best environment as possible, rather than seeing it as a confrontation. If a teacher hears that she was asked to be removed by you, that might not sit well with her. In a perfect world, she might take that professionally, but teachers/school staff are people too, and she (and the school) may be less willing to work with you in the future if you burn a bridge too early.

Regardless, it's great that you are involved and concerned - I wouldn't recommend being any less involved! It's just that strategic and cooperative involvement can go a lot further, especially in the long-term of you and your child's relationship with the school.

Sat and spoke with the Head regarding this punishment - she was not happy and set up a meeting with my 9 year old, the supervisor and herself -  they agreed that football, rugby, cops & robbers are fine and the children are allowed to play.  My son is now "the hero" for getting all their playtime activities back and all the relationship between the boys and the head are wonderful.  The supervisor / caretaker has a few bridges to build but I hear she actually played football with them yesterday!  Valuable lesson for my child that negotiation works....