"Reasonable expectation of privacy" is a constitutional consideration. Some states in the US make covert recording illegal even if the participants are in publ

"Reasonable expectation of privacy" is a constitutional consideration. Some states in the US make covert recording illegal even if the participants are in public. E.g. http://www.dmlp.org/legal-guide/massachusetts-recording-law http://www.dmlp.org/legal-guide/massachusetts-recording-law