My 6 year old son has an account so he can keep track of the caches he visits. I also use the logs as a way to get him to form his thoughts and opinions on his experiences. I just have to keep explaining to him what "spoilers" are -- there's nothing like a log that says, "This cache was fun to find. It was hidden behind some bark in the knot of a tree."
As for drawings: The last event we went to, both our names ended up being drawn, so we declined to take a second item.