cry wolf

cry wolf (to ask for help when you do not need it; to give a false alarm; to cry or complain about something when nothing is really wrong) — бить ложную тревогу, поднимать ложную тревогу; безосновательно паниковать или сеять, нагнетать панику; безосновательно сеять, вызывать, нагнетать панические настроения; баламутить кого-л. без особых причин; || подорвать доверие к себе ложным призывом о помощи

Example 1: He is crying wolf. There is no real danger. — Он просто баламутит всех (бьет ложную тревогу). Никакой реальной опасности нет.

Example 2: In the last 12 years two trillion meals have been eaten containing GM ingredients. The majority of people recognise that crying wolf on this subject without one substantiated health issue is not going to work anymore.

Example 3: Pay no attention. She's just crying wolf again. (thefreedictionary.com)

Example 4: Don't cry wolf too often. No one will come. (thefreedictionary.com)

Origin:
From the children's story “The Boy Who Cried Wolf,” wherein a child sounds the alarm frequently about a wolf when there is no wolf, only to be ignored when there actually is a wolf. (thefreedictionary.com)

cf
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scaremonger(ing)
fearmonger(ing)