Um, it's illegal in IL (I'm pretty sure but not positive) but i learned this past spring (not from persoanl experience.....ehmmm) that it's a good way of keeping track of the deer that have lost their antlers and those who haven't. Good way of finding spots that might hold those antlers you're looking for.

silent.......that's a really good excuse. Hopefully I won't have to use that but at the same time I have had one of my GSP's get loose at night and looked for him using a spot light.