There are many ethical rules that lawyers are obligated to follow. The ethics class is usual a semester in most NY law schools. Hard to teach you everything in the 4000 characters that these answers allos.
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In addition to the prior attorney's answer, see link below for the NY Rules of Professional Conduct. You should be able to answer your questions on your own.
Lawyers do have ethical standards governing our conduct toward clients, the Courts and even third parties who we do not represent. I agree with the other attorney who provided you with a link to New York's Rules of Professional Conduct. You will find Rule 3.4 entitled: "Fairness to Opposing Party and Counsel" enlightening. (see p.19 of the Rules)