Pardon? Are you perchance calling my stance outraged and contrarian
The stuff I saw trickling down the fuselage of an RJ from somewhere around the wingmounts all the way down the sides was bluish green and after I pointed it out, the pilot told me what it was.
The stuff I saw on a 737 flap mount fairing wasn't in hugely noticeable quantities. I just found it interesting to watch its behaviour since I knew that after rotation it was not supposed to be there. It was a grey day so since I was peering through a grubby window, the colour could've been anything from bluish green through to pale yellow, but it didn't leave the wing on rotation and simply froze in the cruise and thawed on the way down.
PS I am not sure what is contrarian about my outrage on this occasion, other than that it may be a stronger view than that of some commentators who may be indifferent. However, I am sure the knowledge you describe might modify my view of the problem. Isn't knowledge like that somewhat beyond that possessed by most ATPLs who nevertheless have to make the decisions about what they allow to be sprayed on their airframe, how often, when and by whom?