No not really. My mother bribed ds with chocolate buttons to go to sleep a few weeks ago. I would never do this but I honestly don't think ds will expect this from me even if my mum does it every time he visits her. If he does expect it he will learn very quickly that it's not going to happen.
I remember as a child knowing that different adults had different rules. I also think it's pretty nigh impossible for others to know your rules unless you specifically tell them. I would only be cross if I had specifically said I didn't want them to do something and they did.
Other than that I actually believe love goes a long way and that we have very little control over how our children interpret what we do.
Sometimes the things we think are for the best are not seen that way by our children even when they have grown up also somethines the things we think we have done wrong are what our children learn the most from and are grateful for - so bearing that in mind I have very few 'rules' about how I want others to treat my children and they are all about safety and respect and not much about discipline.