Normally I'm not on the posting side of the rules question, but this is more tournament rules-ish which I don't know. So, here goes.
I'm playing at a Competitive REL event (a GP) with untapped {Genesis Chamber} out. My opponent casts a creature. Say, {Delver of Secrets}. I know you're required to remind people of some triggers but not others. (Something to do with triggers that are good for them or not?) I don't think I have to remind my opponent to get a Myr, but since I control the permanent I'm not so sure. Could I get some help here?
Thanks.
From what I understand, you cannot forget your triggers. An opponent is not required to remind you of your triggers
Since you control the permanent, it's your trigger. You're obligated to remind your opponent about the trigger, since you control it. If a judge is called on it, you'll probably get a warning for missed triggers because it's a detrimental trigger, as it does something bad for you. Then again, it's up to the judge, but be wary about it.
http://www.wizards.com/magic/magazine/article.aspx?x=mtg/daily/feature/233
Thanks guys. That's not what I wanted to hear, but is good to know. +1s all around.