To object to my 3 year old being put on the spot

[Ticklemonster2]

Just posting a quick query as found mumsnet advice useful in the past.
My parents in law are very pushy/manipulative and want to be in our lives constantly. My Dh and I have drawn boundaries over the past few years to keep our marriage healthy.
I posted recently about some strange things my son has said his grandparents have said to him (when alone with him). Hence not keen to leave him unsupervised with them.
Anyway, recently they have started putting my son on the spot by asking him if he wants to come and see them (despite us visiting 3 times this week and declining the offer due to wanting our own space). They have also been telling our son to tell us when he wants to see them and we will deliver him to them.
It feels uncomfortable and I can see it put pressure on ds. Am I wrong to feel they are using him to manipulate us?

There are a lot of times when as a parent we have to say no.

If DC asks just say no.

personally any one that assulted me wouldn't be around my children at all.

DH is very supportive as they have put us through a lot since we got married. He knows they have issues.
Just to be clear, ds has not visited them alone since my last post. We haven't needed to explain as they rarely had him alone anyway due to MILs previous behaviour. My DH did challenge his mother on the strange things our DS was saying, but (of course) she denied saying things to him.

The only reason we visited 3 times in one week was due to them moving and us dropping things over. We probably won't see them now for a few weeks.
My good old DH is yet again going to have words with them about putting on the spot. The poor guy just wants normal parents!