In Texas you can record someone without their knowledge as long as you are part of the conversation. But there is no leaving hour cell phone in a room and leaving so you can hear or record what the people in the room say when you leave is extremely dangerous and could be a second degree felony in Texas and under Federal law. New Mexico has a similar law as well. However there is an exception in Texas that if there is a reasonable expectation of privacy then the recording can be made even if the intercepter (person recording) is not a party to the conversation. The question of what is a reasonable expectation of privacy is the issue, and it seems in Texas to be a moving target. Therefore I would never advise anyone to record a conversation to which they are not a party. However, if someone did this in the workplace the question of reasonable expectation of privacy might turn on the companies policies and procedure. If the employer makes it clear that there are no expectations of privacy in the workplace then that might be a defense. However, it would be extremely risky defense and there is certainly no guarantee it would prevail as a defense. Juries generally don’t like those who secretly record conversations they are parties to unless they have a really good reason; but they really dislike those who intercept conversations and are not a party to the conversation. This is true in civil cases and also true in criminal cases. In a civil case it might cause you to lose your case; in a criminal case it may cause you to lose your freedom. My advice; never ever ever record a conversation to which you are not a party.