I am going to have to disagree with a lot of the posters here. When you can't be on 24/7, and you might need a flag, it's usually a good idea to have a couple of people with your log-on info. Just be careful to whom you give it.
All of these people who are posting, "%(*)&% your guild if they ask" probably wouldn't last long in our guild. The first time I had to redo a flag mob for 1 person because they unable to be online during a mob . . . well, let's just say they'd be sitting on their ass a good long time outside of raids--and those people who tried harder to get the flag and couldn't (due to numbers, the people knowing his info not being on, etc.) are going to get first pass at the flagging drops like anguish pies or drops of blood in PoBlood, etc.
If you have to, just make a temporary password and give it to someone you trust. Of course, what I wrote is in violation of the Eula . . . but SoE set up the damn flagging requirements, not me! What I usually tell people is that I strongly suggest that they pick one or two people they know and trust, and let them know the info. Also let them know if they have permission to tell it to a guild officer they trust absolutely in case they have to bot multiple people.
Coincidentally, there was one instance where a cleric logged in to discover that he suddenly had a complete epic 1.5 done. . . so there can be benefits too!
Having access to phone numbers of the people in question is a good idea too. Please note, for the careful readers out there, I neither admit nor deny any violation of the Eula, merely that I have encouraged others not to be in full compliance . . .
Chutoi