Yellowjackets have been constant pests in urban environments for centuries. Their presence can be a nuisance and their aggressiveness can easily ruin a family picnic. Yellowjackets can inflict multiple stings which are very painful. Stings can lead to anaphylactic shock and even death of individuals who are allergic to yellowjackets.
For beekeepers, yellow jackets and wasps are increasingly becoming an issue. They can aggressively rob a hive and decimate the colony. It is rapping the best to get the traps out in the spring to increase the chances of the queen.