Mendaero the EK guys do have a problem with it, a recent 2 hr delay in MEL due frost. The reason there is no de-ice kit in MEL is not the cost but the "greenies" so as much as I dislike bean counters it's not their fault this time. There are de-ice "trucks" but they have a 200ltr (approx) drum of heated water, there is not any de-ice fluid as such and perhaps this is what the DJ guys use. Pouring water on a cold wing can result in freezing in areas out of sight but the MEL water system is not used unless ambient temps are >5 deg C.
Its when the inner tanks of the 330 have cold fuel left in them after a long flight and the warmer (new) fuel can't warm it enough that you can get frost on the top. The outers have the same problem if you land with fuel in them. One trick is to transfer the outers to the inners on the ground then top up with warmer fuel. Its could be that the 73s are doing there first flight of the day and therefor not cold soaked?