To expand on that: The human eye cannot pick up violet (or as I call them, blacklight lasers) very well. A true 5mw blacklight laser would be so dim looking that you would need a pitch black room to see it. Most blacklight lasers that are marked at 5mw are actually well over that so they can be seen.
A blacklight laser will not cause cancer or sunburns. The biggest danger with them is that they are barely visible, so they have to be quite bright in order to not look pathetic. A bright light can cause eye damage even if you can't see it well.