I've been on at least one of those Florida departures with "solar de-icing".

I used to de-ice aircraft in RDU and ORD (very different experiences, obv.). De-icing is actually pretty hard work. You have to be tactful enough to spray all areas, and careful enough not to hit the plane with the truck/bucket/capsule usually in poor weather/visibility conditions. Then of course, all of this is under pressure to do it as quickly as possible (but a lower prio than the first two). I can't recall doing any planes in that warm of weather (and my company didn't have any widebody airbuses), but I suspect because the wings are so high on a widebody and it was nighttime, that they did it out of an abundance of caution.