If you try to perform this exactly as laid out in the PDF, there is no chance whatsoever you can do
it without your spectators catching on to how you know which balls each person has. As a matter of
fact, the only way I can see to do this is to be standing behind the chairs and having the
spectators come up to you in a single file line, which will block the audience's view of the
performer. Granted, you will only have to do the glance three out of the four times since you will
know which ball is left after number 3 gets theirs, but it's still not going to fool anyone in the
chairs unless you are behind them and the audience is in front of you. Anyone beyond your 3 and 9
will see how this trick is accomplished. If you stand with your left side showing to the audience
and you are at extreme stage left, you could possibly make this work.
The bag could be
useful for other things, and you could work this routine with proper staging, but it's priced too
high for what it is and what you get.