First of all, Why would you even do this in America? And Second no its not because it disrespects them and you possibly could get arrested for it.
Look at them very, VERY sternly
The teacher looked at the misbehaving student sternly before addressing the class.
Admonish is a verb that means to sternly reprimand someone. It can also mean to give someone a warning or advice.
I can give you several sentences.He spoke sternly to the misbehaving students.I backed down when he glared sternly at me."Follow your orders," the sergeant said sternly.
it means with sternness; in a severe manner.
If it's a meaning you want, 'sternly' means 'harshly' or 'firmly'.
Example sentence - His father spoke sternly to him when he behaved badly.
Firm or unyielding, uncompromising.
Lamented or sternly
They are synonyms, not antonyms.
Reprimanded
Meaning hard, harsh, or severe in manner or character: