One thought that kept occurring to me when I was temporarily deprived of contact with my grandson was 'do you want to be in the right, or do you want to see him again?' There was no contest - whatever it took. I kept my mouth shut and did whatever I could to be helpful, including capitulating on what most people would say were highly unreasonable demands from ex-DiL. Riding it out until her anger and spite switched to someone else was awful, but the benefit was that I got to start seeing my grandson who was in turmoil at home and at school, whilst my son was taking court action to formalise his access. I slipped up once and said that I didn't like what she was doing to alienate my grandson from his dad. Apologised a few days later and explained that we all have a wobble sometimes and asked that she would see it in the context of how she acts when under stress. It was 3 months before I saw him, though, and only because she needed someone to look after him when he came out of school one day.
Three years on, there's a much happier grandson who sees his dad as often as he wants and may be going to live with him when he starts college. I see him every week and email him freely. Ex-DiL is still hostile but doesn't have the power to make my life miserable now. She can't argue with someone who won't engage in an argument, can she? She's busy fighting with another ex now, and has cut off another set of grandparents.
Unhappily, some grandparents may have gone beyond being able to retrieve the breakdown that has resulted in them losing contact with grandchildren. It's a horrible situation to be in and I hope the children make their own informed decisions as they grow up, but for those grans who are still trying to get things back on a civil footing I would say don't engage in arguments and power games - you'll make a bad situation worse. Apologies and offers to help might stick in your throat, but they are nothing like the agony of being deprived of contact with a much loved grandchild.
One final thought - when this thread runs out, why not change the title to something more appropriate? 'Am I being unreasonable' invites posters to consider whether you might be.