Would have to agree with the lady, that missdirection is your biggest aid.
I have never been cought out yet. I do not think that the pass was ever intended as an absolutly invisable move. All the books I have read on the subject advise a very subtle missdirection including rrtcm.
Tips to help its cover apart from missdirection include
Keeping the upper hand as still as possible in relation to the bottom hand.
Keeping it quiet, which is the most important.
There are cover moves available, going into a fan, or riffling the deck are just two which do indeed work exceptionaly well but which I have never found nessecery.
For those who have the rrtcm 5dvd set. There is a great trick on there that is not in the book. Using the pass the spec chooses the only 3 red cards from your selection of all black cards.
After this trick you are set up for ootw
I false shuffle and then get the spec to shuffle.
Whilst looking for the 4 markers you can sort the deck(honest try it they are not as mixed up as you would think, three or four blocks usually and every time you move a block take a marker. To the spec you are just taking four cards)
I explain the first trick as a sort of test to see if they 'had the right sight' or other such rubbish to allow this next phase to continue.
They then have gone from selecting three cards, to sorting out the whole deck, that they shuffled.
If this is all I ever use the pass for it will still have been worth the hours learning it.
As an extra subtle note. On the first trick I first show the deck to be shuffled even though I openly sort, I do this because during trick reconstution all those I ask swear that this was again done before the second phase.
do not think i have exposed anything as you need to know the tricks involved, but if i have please delete
