heavy showers a few hours earlier. was the aircraft parked there a few hour earlier??? was there any active frost present??? again your photo from the 13th of march shows condenation and nothing else. if the flight crew concerned did their walkaround they would have spoted this moisture, checked to see if it was frozen or in the process of freezing, and in doing so carry out the check for any need to de-ice. if they needed deicing they would have done it. every one remembers the BHX accident in 2002 and the air floirda in washington.......flight crew are not idiots and are professionals. you are suggesting that they have as much knowledge of flying as you do........which clearly is none.....you are a buisness development manager adrian. i suggest you stick to it.
how many other airlines do you pull this prank on??? does it get you and upgrade when you fly them again?? are you hoping to get an upgrade with this airline?
If there was clearly ice and snow and a contaminated wing and i was in your shos that night......i would have stood up in the cabin to make sure the aircraft could not take-off.