Imperative be-passive: "Please be advised"

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Please be cautious/aware/vigilant - adjectives. They can all be preceded by "very" but the passive agent, e.g. "by me" cannot be inserted.

Please be very cautious/aware/vigilant

*Please be cautious/aware/vigilant by me

Please be advised - passive form, past participle. "Very" cannot be added and passive agent, e.g. "by me" can be inserted.

*Please be very advised

Please be advised by me.