In general, FRS and GMRS both were intended to be used by families or groups involved in directed communication between members. There is no expectation that people will or are even interested in talking with strangers. If you intend to use FRS for safety reasons please determine first whether a cellular phone might be a better idea. Never carry an FRS radio expecting to contact someone you don't know to report an emergency or get help. Carry a cellular phone for that purpose.
Common sense protects.
Ignorance and inattentiveness can kill. Any kind of car caravan. Any time you travel with two or more vehicles and want to keep everyone together and informed. You can generally stay in touch within a half mile or so while using radios inside the vehicles. Staying in touch at shopping malls.