You’re babysitting your six-year-old grandson. He wants ice cream, but your daughter-in-law (DIL) gave you express instructions not to serve sweets before dinner. What do you say?

A) “Sorry, kiddo. No ice cream before dinner.”

B) “Sorry, kiddo. I would really love to give you ice cream, but your mom said no.”

If you answered A, congratulations! You passed the test.

The best way to avoid potential conflicts is to discuss rules with parents before beginning your childcare stint.

If you answered B, your DIL might become very angry. Instead of taking responsibility for disciplining your grandson, you made her out to be the bad guy. “It’s really a very manipulative thing to do,” says Deanna Brann, author of Reluctantly Related Revisited: Breaking Free of the Mother-in-Law/Daughter-in-Law Conflict. “What’s really going on is, the grandparent is not agreeing with the rule, so they manipulate the whole situation by blaming it on the parents.”

That blame doesn’t just anger your DIL — it shows grandchildren that mom and dad’s instructions are up for debate. “To the parent, it just feels like they’re being undermined, which they are,” says Brann.

Rules for everyday caregivers

Shifting the blame once or twice is frustrating to parents, but not necessarily a big deal. Chalk it up to grandparents’ prerogative — see below. Doing it consistently, especially if you’re a primary babysitter, is another matter entirely.

If you watch your grandkids regularly or your children look to you for permanent daycare, parental guidelines must be enforced — and you must be the one to do it, without passing the buck. “You have to follow the parents’ rules. They’re the parents. You’re watching their kids,” says Brann. “It’s childcare time, not grandma time.”

The reason for this is twofold. Taking responsibility for rules keeps your kids happy because it avoids challenges to their authority, and also prevents grandchildren’s behavioral problems down the line. Kids listen to people who act like they’re in charge.

If you have a problem with the rules themselves, bring it up to your son and DIL privately, away from the children. Then, work towards a solution. “Sit down and talk about it,” suggests Brann. “Make this a problem-solving situation, not a blaming situation.” Remain calm and make sure your intentions are primarily for the good of the grandkids, and not necessarily your own comfort level.

Of course, the best way to avoid potential conflicts is to discuss rules with parents before beginning your childcare stint. “Sit down and talk about what the expectations are in advance,” says Brann. Express your views, but appreciate your children’s right to raise their kids as they wish, with guidelines they can expect to be followed.

“Both parents and grandparents should respect each other’s feelings in the process,” says Brann. Moving forward, cultivate a relationship that allows you to address future issues. “Make it okay for both sides to say, ‘I’m having a problem, let’s sit down and talk about it,’” adds Brann.

The one exception is safety. If mom’s rule says the kids can jump on the couch, but grandma thinks it’s dangerous — grandma wins. There’s no debate about immediate hazards.

Rules for occasional babysitters

Provided it’s somewhat expected at and least grudgingly tolerated, there’s room for rule-blaming if you only occasionally mind the grandkids, rather than act as a full-time caretaker. “It makes a huge difference,” says Brann. “If it’s once in awhile, it can be an inside joke, because typically grandparents don’t discipline often.” The family rules should be enforced overall, but there’s no harm in having a little fun.

If you only watch the grandkids once in awhile, make it a “Grandparent Day” during which the rulebook gets thrown out the window.

In fact, if you’re only going to watch the grandkids once in awhile, Brann suggests, make it a “Grandparent Day” (not to be confused with Grandparents Day), during which the rulebook gets thrown out the window. Eat ice cream for breakfast, watch an extra hour of television, stay up past bedtime — anything goes.

“If it’s a Grandparent Day, everyone understands you’re going to bend the rules a bit, because that’s what grandparents do. That’s one of the privileges of being a grandparent,” says Brann. Frequent grandchild-sitters can also benefit from a Grandparent Day, since it allows grandparents to relax and play around with kids, rather than act as warden.

Ultimately, the goal of rules isn’t to cause rifts in your family. It’s to keep kids safe and give them structure for a healthier youth. When you take responsibility for enforcing them, you become part of that important developmental process — and everyone is the happier for it.

See also: 9 things you shouldn’t say to your grandkids