my next clue would have been another Q==when a laser strikes the correct eyeware where does the beam go?. That's easy its ABSORBED..
- so- if you take what I call an 'over-the-ear-shot' from behind- it can hit the other(INSIDE) side of your glasses and if the angle is wrong it can reflect back into your eye. so just keeping your back to the beams may not be enough 100% of the time,..unless your glasses have side shields. ( and most do)
However, I wonder how would the low optical density (OD of 5 or less) laser goggle withstand the short pulse of laser light (Q-switched laser diodes do exist but thankfully rare - for obvious reasons: $$$. Of course DPSS with that type of optical amplification method - most commonly piezoelectric optical train or specialized LCD between the crystal facet and output mirror - exist.) in term of transmission of the light through the safety goggles (percentage of the pulsed laser light vs CW laser light transmitted through chosen colored glass / plastic material used in the laser goggles). Some of those fancy laser have higher apparent brightness in the shorter time. I can be wrong, but still, like some people pointed out, dyes in the cheap laser goggles can occasionally be problematic. Just wondering out loudly.
Of course, blue lasers are now widespread in the open market (even so, Nichia won't stop you from buying their diode. However they will make you sign the safety compliance certificate - I know because I had to sign a certificate paperwork prior to buying the NVSU233A LEDs. Those UV blacklight LEDs are frighteningly powerful compared to the blacklight blue fluorescent lamps - I wound up having one in a flashlight more for fluoresence test, it can light up stuff up to 10 - 20 feet away. Still, those LEDs commands respect. Blacklight 380 - 340 nm laser diodes are also far more dangerous than the Blu-ray Disc 405nm laser diodes, mainly because they emit surprisingly harsh UV light (365nm looks like harsh purple to me) and they tend to mess up the eyesights easily) - it doesn't mean you can fool around with one. Worse yet, you can still buy the multi-watts Infrared laser diodes, they are SO notorious for emitting scary amount of Infrared lights which can easily burn stuff if you're not careful (you can't see it at all - well, some peoples can, including me - and I still strongly recommend you to use laser goggles specially made for the IR lasers).
Funnily enough, Casio have started soldering the diodes into the heatsink in their projectors, making it almost impossible to extract the blue diodes, it just take a lot of risk-taking and patience to rip them out intact.