We magicians tend to be a very secretive bunch. There are at least a couple of reasons why cocacola would be wise not to tip his hand.
1. He plans to market the effect. The magic world is kinda funny. If someone produces a great effect, someone else will come along and rip it off very quickly, marketing their own "similar" version of the trick. Even in the method is nearly identical, since the method was never actually published, it doesn't matter. In other words, I can take any effect out there and, if I choose, make a very slight alteration to it and market it myself. The magic community is a relatively small one, so this can be damaging to the person who was the original creator. There is actually a big boatload of money to be made from marketing magic effects. I have a friend who makes his full time living from creating and marketing magic effects.
2. He plans to sell the idea to another performer. There are a number of folks out there who make their living by designing effects for other well-known performers. The truth is that most of the "big guys" are who they are becuase of their ability to perform, not create magic. The really big guys make their reputation by the effects they perform and don't want others doing the same effects, so they buy the rights directly from the designer. This would be true of, for example, David Copperfield.
3. He wants to perform this feat for himself and doesn't want anyone out there doing it. If cocacola is making a living performing and has come up with something good, he may not want somebody else taking the idea and performing it themselves.
4. He's a big jerk who's suspicious of everyone and the idea's not that good anyway, but he thinks it is. I've spoken to cocacola via PM and I don't think this is the case.
For these reasons (at least the first 3), the effect itself is sometimes as valuable as the method. The magic world is very different from everything else I've encountered. It has its good characters and bad.
db