I've used them at a couple of games (was trying anything that would beat fogging). I've used ballistic glasses too. Bar none, nothing beats the eye protection that proper quality full seal goggles provide.
I really don't like the "2 inch full auto blast" testing of stuff. I've never seen anyone take a facefull of shots that close. 3-4 feet away...I could see that happening in a bad instance, but not at "contact" ranges. I suppose it's the acid test...but IMO it doesn't properly reflect what happens in the field.
Not all mesh is equal. Some will barely deform/mark...on others BB's will zip right through after the first shot or two where the wires are deformed.
Not all BB's are created equal. IMO it's pointless to say...these BB's don't fragment, these BB's won't/will do this/that. There's a huge variety of BBs out on the fields...of all quality levels. From the sh*ttiest of the .12's to the armour piercing baby killing silicas/nites (just kidding). You can't practically check every BB in every mag...so you can't "make it safe". It's best effort at that point. It is then safer to assume that all BBs will fragment...and to protect accordingly. That might be ok for some...not so for others.
When mesh is used for mouth/cheek protection....that's fine. Fragments or even a penetration isn't going to have the damage that a shot to the eye will have.
IMO...you've got to do what the field/game host says. If someone wants to run mesh goggles and takes a shard in the eyeball...it's blunt to say, but the responsibility is on the wearer's head the field owner. Same with guys who run ballistic glasses. If you wear anything less than proper quality full seal ballistic goggles then you're inherently accepting the risk of taking a shot in the eye. Aside from the field owner, it's no one elses responsibility than your own. (I'll say this though...anyone who's worn mesh and taken a fragment in/close to the eyes changes their tune about them pretty f*cking quick).