 sithina wrote
I'd add "Be Aware and Present while at the Con"--as in, don't be that person who stops in the middle of a moving crowd and causes a pile-up behind them because they somehow managed to forget that they are not just one person at the Con, but one of 65K+ people at the Con. Or, the person who is so focused on their cell phone, map, program book, etc. that they become a hazard to themselves and everyone else when they don't look where they are walking. While it's somewhat amusing to watch these people walk into walls or fall down stairs, it's not as amusing when they are walking into people. Having an inattentive person walk into you and send your coffee, soda, whatever all over you, or knock your stuff out of your hands to be trampled on the floor, is not nice and can be avoided with simple courtesy and awareness of the immediate space around you.  I guess this would sort of tie in to the tip about watching what you're saying while in a crowd.  General awareness might stop you from dropping your most colorfully enhanced f-bombs in an inappropriate place (like the family fun area).

 sithina wrote:
Oversized backpacks are mentioned all the time, but any pack (messenger bag, backpack, rolling bag/cart thing) can be a hazard to others when you aren't paying attention. Most hanging bags are at the perfect height to hit a child in the head, nail a guy in the jewels, slam into someone's stomach, side, or back, knock into a knee or cause someone to trip (though practicing some defensive con-going-techniques of your own will hopefully prevent some of this when these walking hazards are not paying attention to what's going on around them)--not pleasant at all, and likely to cause knee-jerk retaliation of the equally painful variety.  So, if you're wearing a pack or slinging a bag of any kind (and who won't be, especially in the dealer hall?), try and be aware of how much space that bag is adding to your own footprint before you take off.

 sithina wrote
I'm one of those people who, though often randomly spacing out, is also strangely hyper vigilant of what's going on around me, who's in my immediate vicinity, who's walking in my direction, from the side, whatever that I may have to clear away from (if it seems like they aren't paying attention), be super aware around blind corners and such, etc... I developed it years ago when I seemed to always walk up on people (scaring them half to death, apparently), or get walked on when people didn't hear me, because I walk fast, but quietly (which I also didn't realize until around that time, lol), and I don't fidget much when I'm just standing around. My fiance always laughs and tells me that he takes his cues from me when we're out and about, and that he'll never have to worry about getting blindsided in an apocalypse because I'll see or sense the threat coming and just ninja my way on out of the situation ^.^;