It is not advisable to get any piercing (earlobes included) while on vacation for a couple of reasons. The main reason is that you shouldn't swim with fresh ear piercings for 6-8 weeks. Basically piercings are puncture wounds, and submerging them in chlorine, beach water, or lake water can be problematic. Chlorine is very strong and can make fresh piercings red, itchy, oozey, etc. Any natural body of water (oceans, lakes) is inhabited by bacteria that can enter the body through the wound (piercing). This can cause infection or illness. It would be no fun to have a little one with infected earlobes while trying to enjoy WDW!