when getting events with event.get, there does not seem to be any way to filter by the maintenance state back when the event happened. this makes reporting on historical events impossible.
it would be great if we could have a flag to filter by any/in_maintenance/out_of_maintenance states.
not sure how easy that would be - there does not seem to be information like that stored anywhere, and recalculating maintenance periods is not feasible (those could have been removed or changed, too). might require storing state for every event, maybe ?
triggers that reference items from multiple hosts would also have to be handled in a sane manner.