That's one reason I'd have rather used a L6-50. The L6-30's at work (each computer cabinet is fed by L6-30R hanging from conduit+box and UPS's built-in 8 foot cord and L6-30P reaching up to connect) were easier to plug in and unplug than my 14-30 on the dryer at home. So I suspect a L6-50 would be easier than a 6-50. Yeah, those straight-blade connections won't fall out without a lot of force from somewhere.
The 309's do have the advantage of a shroud.
