Penny - Yes, using a flashlight to spot baskets is illegal at WW Glow League. I would also like to point out that using a flash light at all is detrimental to your night vision and the night vision of those on your card. Everytime you use light you see less and less. Playing the entire round in darkness is the way to go. Somtimes though, if there's enough snow, a bright moon and some cloud cover it doesn't matter anyways because the whole park is awash with light.
Now that Glow is catching on, good luck to those prospective leagues. May you find oodles of success. Be sure to check the policies of the parks you are in though. Some parks aren't open after dark. Water Works has an actual time of closure regardless of the darkness, so it works out for us. If you find out that your park actually has a sunset closing time or something along that line, get a little group of well dressed well spoken individuals to plead your case to the local authority.
Good luck, glad to see glow becoming so popular.