Yes, he should, but the better support answer is to say it, rather than giving a cute answer about putting it in a shirt pocket. Gets back to the question of poor/ambiguous instruction. We're all stupid at times and ignorant at other times, even the same time, sometimes. Giving him the real answer gives him information to extrapolate into other areas too.

Wasn't disagreeing with this sentiment, just trying to explain things.

As far as the correct support amswer is concerned yes I could have given him the right answer but then he would have said that he has been doing it for the past x days and the phone worked fine. Then there was this issue of a potential embarassment where I would have given him a simple solution where he could have figured the solution out by himself. So the answer given was more to save face and give the other person time to understand the issue further until we got a proper resolution.
As a tech support I feel that it is essential to understand and acknowledge the person before tackling the technical query.

My inexpensive cell phone (with no cover) requires me to press one key for several seconds, then press another to confirm that i really mean to power down. Keep it in my pants pocket all the time, with no problem.

Rather than snicker at your customer's cluelessness, it seems better to pass this difficulty along to your engineers, so that they can come up with a more intelligent and trouble-free design. In other words, take a cue from this customer, and come up with a better product.