Seems to me they mandated the gas stays *in* rather well; but not that the gas comes *out* gracefully.
The cost of the complexity is (it seems): a) The increased spillage of gasoline b) The increased vapors from gas left in the can (see note 1) c) The increased cost & complexity of the spout d) The increased time it takes to pour the gas out
Note 1: I can't get all the gas out of the can with the spout on. I presume all that gas will vaporize and fill the can with gasoline vapors, which, will stay inside due to the lack of venting and permeability - but - they will immediately escape the moment the spout is removed for the refilling tasks.
Given that we spill more, and we vent more when we open the gasoline can to refill - yet - we certainly vent *less* during storage and during the pouring tasks ... I wonder where the balance of the equation lies?
Does anyone know of any data on what we're actually saving in vented gasoline vapors?