Actually, most 'lasers' aren't true lasers, but simply focused LEDs. If you look at the module itself, there is a lens and adjusting ring arrangement on the front. Adjusting the ring will change the focus of the LED. You could de-focus it slightly for a vortex.
But then you just get into a downward spiral [pun intended]...if you use a 20mw laser and de-focus the beam to cover 4x the area and be more 'eye safe', why not just use a 5mw laser? I don't have all the math equations in front of me, but it would seem 5mw over a certain area would be as bright / do the same damage whether it came from a 5mw laser focused to a spot, or a 1000 watt laser spread out over a couple square feet. The thicker beam might 'appear' to be slightly more visible from off angles, though.
As far as shining in eyes, a lot of that can be avoided with a good location. ie - if people are walking down a path, the edges of the beam can be off the path and the top can be above peoples heads. Then the only place they walk through the beam would be at the bottom - and you could possibly put a 'scare' there to keep people moving along and not gazing into the beam.