Should an event logo contain a date and a year? Perhaps it is not known yet if it will be an annual event. Would just having the date be specific enough?
This is more preference for the designer/client. An event can easily have or not have any dates integrated directly into its logo.
If it's unknown whether the event will be annual, but the year/date is desired by the client, then one should design with date modification in mind.
These are merely some random Google finds as examples. You can see the date is placed and designed in a manner that allows it to either be easily removed, or easily edited. It's not overly integrated with other elements. There's merely some attention to aesthetic harmony where the date is concerned.