Bob Owens, writing at PJ Media, has the incredible story of ATF agents intercepting some toy guns at the Port of Tacoma, and then twisting themselves into knots trying to make it appear that they were dangerous.
Both Airsoft Outlet Northwest (the retailer/importer the Airsoft guns were seized from) and AirSplat (the nation's largest Airsoft retailer) stock and have experience with the various configurations of the WE Tech Airsoft gas blowback systems, and both claim to have had experts attempt see how these toys could possibly be converted into functioning firearms. Airsoft Outlet Northwest took a previously delivered (without incident) WE Tech to a gunsmith that specializes in the AR platform. The gunsmith determined the following:
* The WE TTI M4s lack any sort of functional gas tube which is integral to an AR15's operation
* The upper receiver of an AR15 fits onto the lower of the WE TTI M4
* The stock trigger pack in the WE TTI cannot strike the firing pin of a AR15 bolt
* The body of the WE TTI lower is several mils thinner than an AR15 lower, and shims would be needed for any AR trigger pack to work
* The trigger pack of an AR15 appears to be able to fit onto the lower receiver of a WE TTI M4, one of the AR15 trigger pack retaining pins is impossible to insert without major modification, and the hammer isn't operable with the WE TTI lower.
In short, the gunsmith determined that the entire upper receiver would have to be replaced by an upper from a real M4/M6 type rifle to have a hope of functioning, and a trigger pack from a real M4 would have to undergo extensive modification to even fit. And even when modified to fit, it wouldn't fire.
I don't know about you but I feel safer already.