It is so important that children and young people understand the concept of consent - in all aspects of their lives. Whether this is consent and information in respect of the law in relation to sex and healthy relationships, or whether it’s consent to very basic things like whether they want to do something or not (like go to the cinema with their friends).
The impact on them and others definitely comes in to how significant this incident was. And for some people to say “but it doesn’t matter, they didn’t give consent” is a bit too simplistic. Life isn’t as black and white as this.
We all do things we aren’t 100% sure about - mostly to make other people happy, or for “the greater good”. Does that mean we aren’t consenting? I’m not so sure. For example, today my little girl (11) didn’t want to go for a walk. But everyone else did so she went along with it. The impact on her was minimal. In work we are provided with LFT’s and asked to do them x 2 per week. It’s not mandatory. I don’t like doing them, I’m not sure how reliable they are. However, the tests have picked up positive cases of Covid which has reduced the spread of the virus around my colleagues. So I go along with it and I do the tests. The impact on me is minimal. I could come up with loads of examples of children, young people and adults making similar decisions.
This is VERY different to a medical procedure that is life altering, or medicine being injected into my body, or me being the victim of a sexual assault. Because the impact of these is significant.
I’m not saying that we should teach our children to always go along with low impact things to make other people happy - but I do think we need to acknowledge that sometimes we do go along with things as a way of compromising.
I suspect in this case your son heard what the nurse / teacher had to say, thought it wasn’t a big deal and just did it as the rest of his class was doing it. He therefore gave consent - but maybe wasn’t 100% sure given the discussion you had with him previously.
We do need to be careful that children and young people know the meaning of consent and I do not want it to appear as though I am minimising how important this is.
If he was genuinely “coerced” then that’s a different matter. I would want to explore that a bit more with him before contacting the school.