1. Don't hit someone in the face with your umbrella. Be aware of your umbrella's edges at all times. When walking down a busy sidewalk, lift the umbrella up to allow others to pass under it safely. Others reserve the right to yell UMBRELLA! very loudly at anyone who does not do this.
2. Do not hold up pedestrian traffic to open or close your umbrella. Not even for a second! I know, I know, it's raining, but get the fuck out of the way.
3. Do not use your smartphone while carrying an umbrella. What!? Seriously?! Yes. If you're looking down at your phone—texting, e-mailing, whatever—you're not paying attention to your surroundings and you're not making sure that you won't be smacking someone in the eye with the pointy bits of your umbrella. If you want to carry an umbrella, you've got to sacrifice your tweeting.
4. Don't shake the water off your umbrella around other people. C'mon, man, that's just rude. (YET IT HAPPENED TO ME ON THE BUS THIS MORNING.)
UPDATE: Here are two more great tips, thanks to our wise commenters.
5. Save the space under an awning or bus stop shelter for someone who does not have an umbrella. You already have something covering your head, so let someone who doesn't get out of the rain for awhile.
6. Please don't put a wet umbrella on bus seats. The buses are already miserable enough when everyone's cranky and soggy. Don't make things worse by leaving puddles on the seats, too.
And here's another idea: I propose that the city hand out buttons for people to pin on every person who hits them with their umbrella. When someone collects 10 pins, they lose umbrella privileges for the season. If it's a tourist who collects 10 pins, they are BANNED FROM SEATTLE FOREVER.
Have any other suggestions for the umbrella carriers, Sloggers? Hopefully we can get through the wet season without someone losing an eye.