Just because evidence was not lawfully obtained (ie. call recorded without other the other party's consent where that is requirement of state statute), doesn't

Just because evidence was not lawfully obtained (ie. call recorded without other the other party's consent where that is requirement of state statute), doesn't necessarily mean that evidence can't be used to protect yourself against a more wide-ranging claim. The various precedents against the use of tainted evidence are mostly used in favor of a defendant and against the state. A $50 misdemeanor fine for unlawfully recording a phone conversation, may well be a small price to pay - if the content of that recording can successfully protect you from a potentially bankrupting civil case. And you always have the option of not disclosing the recording if that is your lawyer's recommended advice.