Last August, I caught up with a some friends over coffee on the first day of school. Since I'm always on the lookout for good travel scoop, I quizzed people about their summer trips.

I made an astonishing discovery. Of the ten people I chatted with, half had vacationed with their parents or in-laws since I had seen them last.

Half!

Now I'm no statistician, but I know a trend when I see one. In a word? Grandcations.

Grandcations can be great---I've been on three very good ones myself. Your kids bond with their grandparents, you all get to go somewhere new, and everyone gets a break.

But it's not all sunshine and pina coladas, my friends. All those things that drive you crazy about your parents at home? Will still drive you crazy in paradise. Here are a few Grandcation pitfalls to watch out for:

Too much noise = No Naps

Most grandparents I know would face a charging grizzly bear for their grandchildren. They would run into a burning building. They would lie down on train tracks. So why can’t they be quiet while your baby or toddler naps? No one knows. Maybe they've forgotten how. Maybe they're going deaf.

I’ll never forget my daughter’s first Thanksgiving. She screamed in a portable crib in a nearby bedroom while I sweated and choked down mashed potatoes. Every time she started to fall asleep, my beloved father-in-law’s booming laugh would wake her. Then he would pat me on the hand, and say, “Relax! It’s not bothering us.”

I was pretty sure I was going to kill him.

Big family dinners

From unrealistic expectations about how long kids can sit still (about 4 minutes, as we all know) to wildly inappropriate food choices (too spicy, too fishy, too yucky), Grandcation dinners can be a terrible trial for everyone. Also, they often conclude with enough ice cream to choke a horse. Or chocolate cake just a few minutes before bedtime.

Try lobbying for an early dinner for kids (with food they'll actually eat). If that doesn't work, try having another glass of wine.

The brat pack

Lack of sleep, routine, and protein all unite to form the perfect storm, usually around day three. You are desperate to look like an effective parent in front of your own parents, and your kids can smell this on you like a dog smells fear.

Your face is frozen in a smile of rage as you hiss orders that no one hears or heeds. Your parents would like to offer some parenting pointers, but bite their tongues off instead. The kids alternatively sulk and run wild. Good times!

Waaaaaay Less Babysitting than advertised

But it’s all worth it, right? Because you and your husband are going to spend a LOT of time alone while your parents watch the kids. Not so fast.

Let’s say, for the sake of argument, the typical Grandcation day is about 12 hours long. Up to 3 hours will be devoted to eating, and eating-related activities. Of the 9 hours remaining, plan to spend a full 2 hours deciding what to do that day, 1 hour grooming, and 2 hours submitting to “candid” family photos.

Now set aside 1 hour for daily trips to the grocery store, 1 hour for hunting for misplaced reading glasses, and 1 hour for applying sunscreen.

You’ve got 1 hour left for lunch with your spouse—hooray! Of this, plan to spend 15 minutes leaving instructions for your parents and another 15 minutes showing them how to use their cell phones.

Have fun. Don’t hurry back!

Jamie Pearson is the publisher of the family travel website Travel Savvy Mom. She is lucky to have parents and in-laws who want to vacation with her at all.