Yes there are many different circumstances in which one would like to appear skilled with the cards, and many where it would be a detriment.
If I am doing a gambling/card table routine, I certainly
would use a few flourishes. You see in this case I
want it to look like I am a card sharp, and laypeople react very well to even the most simple of flourishes.
Of course this is quite contradictory to the way in which a
real card sharp would act on the gaming table; in this case he would wish to blend in with the other players and not give the slightest hint as to his skill.
I think this closely compares to performing card 'magic'. I do not want to give the spectators any reason to suspect I am skilled with the cards and therefore I avoid doing anything flashy or unusual. But you
can get away with unnatural moves, you just need to develop that other very important skill which a magician must have - presentation. You must be able manage both the audience and the circumstances, but without them ever suspecting that you are in complete control, just like a real card sharp. If you master this (and I am barely an apprentice!) then you will be able to get away with just about anything you like. You could palm an elephant.
I'll try and explain what I mean.
Right then, Gammelsmurfen. As you say, something as simple as a 'get ready' or an undercut can look very unusual to a layperson and can attract attention, but these moves should not be discounted.
You mention the riffle force and you're right - it is a bit unusual. I mean, give the deck of cards to a spectator and ask them to perform a 'pick any card' trick and watch the way they do it. Normally the cards will be passed hand to hand in a very rough fan. This is the most natural way to do it and is the reason why the classic force is so effective.
But this does not mean you cannot use the riffle force, or any of the other several hundred forces out there! I use the riffle force loads, and, in fact, several other moves which you would never see a layperson do. And how do I get away with these? I just employ a little skill in presentation.
You see, us cardies have to use subtle tactics to avoid arousing suspicion when we use these moves. For example, I use the riffle force when I have a pen in my other hand, which gives me enough excuse to start an unusual one-handed move.
My 'get ready' for the D/L also varies depending on the circumstances. This is naturally a suspicious action and troubles a lot of beginners. In my ACR, I combine the 'get ready' with the 'magic move' that needs to be performed to make the card jump to the top - you know, riffle the pack, snap your fingers etc etc.
In this case I simply hold back the number of cards that I need when I riffle, and Hey Presto, a suspicious move is completely covered. Easy!
If you need to, you can give yourself an excuse to perform the more suspicous actions. This can
always be done -- just use your imagination and your personality.
Ok... My point is that card management is only part of the deal here, the rest is knowing your audience and manipulating the circumstances so that you are in control.
Both of these skills should be practiced, well studied and performed with such aplomb that your skill passes by as gracefully and silently as a boat in the nighttime.
