The way that “official” signs are worded, especially at airports, has always bugged me. Take this one from the gate at San Jose airport for example:

  1. All checked and carry-on bags are subject to search. - Ok, sounds good.
  2. All passengers are warned to control their carry-on baggage etc… - Errr, first up, am I being asked to do something, or am I being told that all passengers have been warned about something. And why “warned”.
  3. All passengers are advised not to accept items from unknown persons. - Are they? Cool! Oh, were you asking me to do something?

Maybe I'm being pedantic, but why not:

  1. All your checked and carry-on bags are subject to search.
  2. Please keep an eye on all your carry-on baggage etc…
  3. Please don't accept items from unknown persons.

Seems better to me.