I’m more interested in how this story got leaked. Obviously the crew would file a report with the higher-ups, but how much others get their hands on this photo? I wonder if one of the FA’s sent it to the media.

One possibility is...plane returned to the gate, if anyone made a PA as to why, a pax could have snapped a photo of the wing and posted about it online

The plane came in the day prior in nasty icing and snow conditions and the return flight was canceled. They got deiced the following day when there was no precipitation and were advised by the deicing provider that the aircraft was clean. Our (F9) procedures require the crew to do an "exit row" contamination check if the HOT is exceeded or if operating in heavy snow. While neither of these conditions existed at the time, it seems something made them want to check (and what a good call to do so!).

They went back to the gate to deice again and were told by the vendor that fluid had run out (not sure if it was type I or IV). It's hard to say whether the fluid ran out immediately after they got deiced/anti-iced, or during.

Fantastic catch by everyone involved on the airplane.

I wonder if it was pax in window seat(s) who notified the flight attendants.

Standby for “because Frontiers bottom feeding lowest cost de-ice vendor **** themselves, you all are going to have to wear diapers”.

Yup. Regional pilots have gotten in trouble in recent years, launching with "trivial" ice/frost (even loose, blowing snow flakes) and no de-ice, only to have a PPL or "aviation savvy" civilian send pics to the FAA. I arrived at a plane early one morning and the station manager pulled me aside and said one of the pax was concerned about a little frost on the wings... "OK, so de-ice us". Turns out they were one of those rare warm-weather coastal stations which wasn't required to have a de-ice capability. Hung around drinking Joe until the sun came, then taxied out to the end to thaw the ice in the sunlight, taxied back, got the pax and off we went.

Looks to me like they ran out of type 1, and maybe sprayed cold T-4 on the ice

For sure. If that was a full boat with a lot of gas, good chance it would be leading all of the news services right now.

And where do you draw the line? Are we going to start checking bolts are properly torqued down after maintenance?

Agreed! Good catch by the FA. This could have ended in disaster.

From what I heard, they ran out of Type I and the de-icer just thought he could apply Type IV on top of the snow and call it clean.

I heard that once this was reported, the particular de-icer was immediately fired and the company's contract was terminated.