I've never heard of it either. We do not walk the dogs in the summer time here. It's 94 with 86% humidity and the only time to walk would be early AM (like 6:00 AM or 8:00 PM) and that is when the bulk of the mosquitos are out and about.. It's a dicey situation when one is swatting bugs and trying to leash walk the dogs. It's easier for me to just let them run themselves in the back yard for 15 minutes four times a day.