OP, I agre with you. While I wouldn't say anything to another passenger, I would not be upset with someone who would. I don't like when people ignore the announcement (which is a requirement - NOT A REQUEST), because it shows that they do not take direction well. I especially hate seeing people in First/Business Class ignore this requirement. Why? These are the same DYKWIA passengers that quickly pass judgement on others for "not following the rules" in life. Moreover, the argue that the rule "really doesn't matter." Well, whether it matters or not is not the point. It's a requirement, and everyone is should follow it. Not doing so makes you just as bad as a common criminal who doesn't think the rules apply to them.
One last thing, I hate that Flight Attendants are selective as to who/when they enforce the rules. Sometimes I wonder if they are afraid to chastise certain passengers. Guess the point is I couldn't be a flight attendant, because I would enforce rules.
Another thing...When some "undesirable" shows up on the news/youtube.com for not following the rules on a flight, frequent flyers are quick to pass judgement. Yet, they do the same thing. That's what is worst about the entire situation. Enforce your laws on everyone but me....