It is ingenious and once you see the product and how it works, you'll wonder, "Why didn't I think of that?"
Seattle's Pacific Science Center is a bit like San Francisco's Exploratorium, only much bigger. So, when Brandie Booth took her daughters there recently, she knew it would be easy to lose track of one or the other.
"I was explaining dinosaurs to one of my daughters and she went to play with a sand thing they have here and all of a sudden she realized, 'Where is mommy?'" Booth recalled.
5-year-old Indyanna was quickly reunited with mom and sister. Then, a little while later, 8-year-old Tea went missing.
"It was time to go and I am looking for my daughter, and I couldn't find her," Booth said.
Again, she was quickly reunited.
It wasn't luck that brought the family together -- it was tattoos. Brandie had read online how you write your cell number on the temporary tattoo, so if your child is lost, they can point to it and ask for help
"One of the mom's had posted about this product," Booth told 7 On Your Side. "I thought, 'That looks very cool. It looks very handy.'"
She bought them and used them that day at the Science Center.
"The kids think they are really, really cool," creator Michele Welsh said.
They say necessity is the mother of invention. Welsh came up with the idea after taking her three kids to an amusement park on Memorial Day.
"I became so nervous we needed to leave, it's too crowded, and I said I can't take it. I took a deep breath and instead I took a ball-point pen out of my purse and wrote my mobile number right on their arm," she said.
And, the idea behind the safety tat was born, which brings us back to Tea and Indyanna, and just how easy these temporary tattoos are for mom to apply and the kids to use.
"Call the telephone number on it," Indyanna said.
"You have to show it to the staff and they will call my mommy," said Tea.
A pack of safety tats start at $7.99. They come blank with a pen or preprinted with your phone number and allergies.