Best trick I have learned here is: When going to big amusement park, zoo, museum or other crowded public places with little kids that might get lost and are too young to memorize your cell phone number, you write your phone number on their arm in sharpie, just in case!
I never would have thought of that b/c writing in marker of any kind is not something I would ever think to do to my child but when weighing the pros and cons of loosing a child or writing on them in ink...I take the ink any day!
Riley J. gave this brilliant piece of advice that has (sadly and scarily) actually came in handy once when my in-laws took my kids to the Portland Zoo a few summers back! I was so thankful that I had heard of this and thought to do it!!!