I'm using OSX 10.8.2 iCal on my mbp, with an iPhone 5 and iPad 2 running iOS6 all syncing via iCloud.
I have a lot of recurring events on my calendar that I do not need alerts for. These events have alerts built into them. When I delete the alert from ANY device they re-appear and I continually get the annoying alerts daily. I've tried to delete them using different devices, but they continually come back.
For example, every day at 3PM I have an event to pick up my son from school. Originally I had an alert 10 minutes prior to 3PM that I would get the alert. I don't want it to appear any longer. I've gone into the event (tried on all three devices and icloud.com for that matter) and removed the alert from the recurring event. When I save it I choose "For All Future Events".
The next day, the stupid alert is back!
I know I can turn off alerts via iOS and OSX, but thats not what I want to do. I only want to change this for a few events.