Our grandson was and is cared for within a large family unit. Distance means we’re rarely involved now although until he was 3 we were regular minders.
Because it was important to us all he felt comfortable and settled his Mum explained - verbally, no lists - the important things in his day to day life such as nap times and food requirements. They seemed to change weekly! Outside of that we all had our different approaches to fun times, he enjoyed spending time with us all and had a wealth of experiences.
No one had or has a problem with it, he was and is happy to go to the different places and people, his ‘minders’ were and are happy as were and are his parents. We could also at any point ask his parents for advice, both provided it quietly with no sense of blame or judgement. It was useful to be able to check in when we were uncertain if when as a toddler he bumped himself. .
Surely that’s enough? No need for stringent rules which seem to be more about anxious parents than the comfort of their child.
Try not to stress about this j916, it feels personal but actually isn’t. If there was real concern about you minding your grandchild you’d simply not be doing it. Their stance may feel ott to many of us but for the parents it’s their preference so best try not to let it irritate and follow as closely as you can.
Whether reasonable or not in your view it would be sensible to adapt to the parental wants The baby will be a toddler soon enough and before you know it off to school. Enjoy this time, rise above the comments and no, you aren’t being unreasonable. Your feelings are your own, you are trying to do your best. Adapt a bit if you can, keep the peace, but don’t stop enjoying precious time with your grandchild.