Typically the events in my calendars do not require alert times. However, I have an automated scheduler where my clients can book themselves onto my calendar without my knowledge, so having a reminder of their appointments is crucial to my dependability. Right now the option is to have a default reminder to all calendars or none and it would be a luxury to be able to set a default reminder specific to each calendar. I know I can simply delete the reminder when creating the events in all my other calendars.. it's just a small step that would be lovely to be rid of :)