A classic line from Eclecticity: Beware of Ensigns with clipboards.
Beware of CEOs who've just read a business bestseller.
Beware of bureaucrats who want to study your area.
Beware of politicians with a "comprehensive" plan.
Beware of speakers who "just want to say a few words."
Beware of door-to-door solicitors who "don't want to sell you anything."