Now this is confusing...
If they serve the intended purpose as you have mentioned then why the hell Toyota's Official Dealership removed these in front of me...and upon asking they said what I shared earlier.
It's good then that I collected all these as they threw these in the waste bin...
As for acting as a one way valve system to stop dust entry...I have serious doubt that they are of any use as their fitting is pathetic & so loose that they keep coming off on each car wash... lol
May be IMC saved money here too...
Well if there are any Corolla owners they can check if these are there or not? If yes, is their fitting as pathetic as Yaris?