Thanks all, for the replies.
I agree with the comments re crosswind landings and such. There is a real effort in the US to teach that the case of slipping while on approach is a specific exercise, different from slipping in other areas and deserving of a special name, "Forward Slip". Students are expected to treat this case as special, not because of its hazards but because it has that special title. This makes it a big deal and causes many students grief and confusion lest they get it wrong in the test.
My campaign is to de-identify the slip on approach from all other slips, and simply identify the slip as any case when the ball is not centered. Of course the cross controls used on approach might be considered rather extreme, depending on the airplane and its characteristics. I believe de-identifying the technique would make learning the procedure, and understanding the effects of controls, easier for the average student.
Confusion as to the best way to slip the airplane when flying into small strips has been identified as a contributing factor in some accidents and I think the terminology has something to do with that.
As an aside, I was always amused when giving a landing in the B747 to First Officers of an Asian airline that shall remain un-named, when they would set up the airplane at around 300 feet with cross controls, so as to offset the drift of a crosswind, and fight to maintain that all the way down to landing. Setting the bank and rudder in close proximity to the ground was way too frightening, and as for crab, forget it! Never mind that the wind at 300 is not the same as on the ground (I have seen it change from right to left crosswind in the last couple of hundred feet, with no change in the FO setup of controls; imagine the result) and that if the rudder and ailerons are offset enough, there will be a degradation of lift, just when you don't want it. I don't know how, but they all managed to avoid a pod strike, did not need my hand under the controls to stop excessive aileron, as it turned out. So maybe I was the one confused.