Proof of our society's decline is that Halloween has become a broad daylight event for many. ~Robert Kirby
But is it really that bad?
What I see these days is fear of letting your kids go up your street without an armed guard and an SUV patrol car. Our fear is fed by the media, which places a magnifying glass on every incident or rumor that happens, especially when it is rare or sensational. Certainly it depends on where you live, but the large majority of us do not live in a zip code like 48204 (most dangerous neighborhood in the US) or anything close to that. If you do, ignore this.
I’m not suggesting I know better than parents how to protect their own kids, you have to make the decision, but we are a little paranoid these days. While caution protects, it also restricts growth, confidence, and decision making.
Supervise but don’t smother. At least let your kids think they are on their own, if only to let them feel some independence. And really, I don’t think you have to have their candy X-ray'd at the hospital or have the special treats, made by the nice lady up the street, thrown out for fear of poison. Take the 2-5 year old kids to the "trunk or treat" event. Let the older kids have some adventure.
Although reported and discussed every Halloween, the poisoning of Halloween treats has just never happened. See:
http://www.snopes.com/horrors/poison/halloween.asp
As a metaphor, teaching your kids to swim (to be independent) has some inherent danger, but if they know how to swim (independence), they will have a tool (getting by using their own senses and experiences) to combat the danger of drowning (bad people).