A post on the art and craft of fannish volunteer-run conventions. These are my opinions and my experiences. As always, YMMV. All of these posts are available here: http://www.boston-baden.com/smofs/conrunning/
I was at Ani-Jam in Fresno, in 2012 (their 7th year), and late Saturday afternoon they made an announcement over the convention center PA system. They were telling the members that if they had a one-day Saturday badge and wanted to come back tomorrow, they wouldn't have to pay the full Sunday one-day price. They could apply what they'd paid for Saturday and pay the difference as an upgrade to a full weekend membership. And two things hit me like a bucket of bricks.
First, that the policy they'd announced has been a standard registration option at many conventions I've been involved with, such as Loscon and Animé Los Angeles.
And second: in that 90-second announcement, they'd done a better job at publicizing the upgrade policy than we had ever done. If your convention has a policy like that, who's in on the secret? Is it published on the website, in the program book, on signs, on the at-con and pre-reg sign-up form? I've been thinking that a sensible thing to do would be to print the upgrade policy on the back side of the one-day badges.
There's a bunch of things that you could put on the back of the badge. Animé Los Angeles has a design that incorporates the year and the color coding used on the stripe on the front, so when the badge flips over you can still tell if it's a current badge and whether it's a full-weekend or one-day.
The Program Operations department at a number of conventions will print stickers to go on the back of the program participants' badges with their complete panel schedule. Something that I've done is print my own name labels, and when there's nothing more important on the back of the badge I can put my name there, so if it flips over you can still see who I am.
(I met someone for the first time at Sugoi-Con in Kentucky in 2007. He introduced himself, said he was on the board of directors that oversees the convention, and explained that he didn't wear a name badge because "everybody knows him." I don't think he saw the irony.)
Some conventions will print little slips with useful phone numbers and slot-punch them, so they can hang on the back of your staff badge. And if you can borrow the slot punch, that can be a convenient place to put your mag-stripe key card.
Sac-Anime in 2012 had saw some interesting uses of the space on the back of the badge. The regular attendees had a map of the facility. The staff badges had the same map, but some additional staff-only rooms were shown. And the dealers had the setup hours and operating hours of the dealers room on theirs.
A common thing I've seen is to have legalese boiler plate on the back of the badge. "This badge is the property of the convention until it's over" meaning they can take it from you if you break their rules but it's okay to keep it as a souvenir after. Or they'll have their Code of Conduct or TOS or EULA on the back, so you have them with you at all times. (I'll check my badge collection to see if I can tell you some of the conventions I've seen this at.)
Finally, if you're implementing any of these ideas, don't forget it consider whether to print it upside down or right-side up. Right-side up means it's that much harder to read the back of your own badge while you're wearing it.