gmonkey42 | not sure what to do about this

Someone e-mailed me asking for permission to use my picture of Captain Petunia in my Pirate Monkeys Inc. banner as the logo for their youth hockey team. If it were a web site wanting to use it, my answer would be the usual "you can use it if you give me credit and link to my site" but a hockey team is different. It's not a business but at the same time, I'm a little nervous about protecting my copyright in this case. If they asked me to design a logo for them from scratch, it'd be different. The thing is: I plan on eventually doing more with the monkey characters, maybe a webcomic or Flash cartoons. I don't want to go and say 'no' and lose an oportunity to publicize my site but at the same time, I don't want to give them permission and later have a lot of people asking to use it and I'll have set a precedent letting people use it. And it's not like my site makes any money so I wouldn't be a sponsor, therefore I wouldn't be in as much of a position to ask them to include my URL with the image.

Arrgh. So what would you all say? I'm leaning towards 'no' but I'm undecided.