I live in an area where dreads are really common (Humboldt Co.. Ca).
It seems like the people who have them are often scratching their scalps. Do dreads cause itchies, or do they collect fleas? It's probably an unfounded stereotype, but our area is experiencing a severe influx of "travellers", and dreads are associated with folks w/out access to bathing facilities, as is the odor of patchouli.
When I was growing up (my late teenage/early 20's), dreadlocks were worn by people who believed in the Jah religion. Mostly people who had travelled to Jamaica, and studied under some guru type Jamaican sage. I had respect for those folks, as they practiced what they "preached" (as far as the whole "Jah love" thing goes) Now I see people with dreads (they could just as easily have long, soft flowing hair, or crew cuts) starting fights, carrying weapons, robbing people, etc. The religion is lost. I think that if you're wearing dreads for religious purposes, it's nobody's concern. If it's a fashion statement, then be sure they are well cared for. Otherwise, stick with the removable dreads, so you don't have to deal with the upkeep.