To whom are you giving those guidelines - anyone in particular?
By the way, even though I don't spell the word that way, my collegiate dictionary says that "dyke" is a variation of the spelling of "dike". So either spelling is acceptable.
A "dyke" is also a term for the white crossed canvas webbing used to secure a cartridge box to the rear of a infantryman in the Napoleonic age of combat.
dvwjr
Probably only to those who are smart enough to care.
By the way, even though I don't spell the word that way, my collegiate dictionary says that "dyke" is a variation of the spelling of "dike". So either spelling is acceptable.
Through mass ignorance "preventative" has also become an acceptable spelling for "preventive", but a well educated person knows the difference. It affects credibility. If I hear or see someone claiming to be a doctor say or write "preventative", I immediately discount their medical expertise.
By the same token, when an American uses "dyke" in a discussion of flooding, they MAY know something about lesbians, but probably very little about levees.