When is it legal to record someone who is not intending to be recorded?
<p>In Canada if you're a party to a conversation you're allowed to record it without other's knowledge. What if you're not a party but someone is talking very loudly? For example you want to file a noise complaint about your neighbours? </p>

<p>Also what if it's an accident? Say you're recording a private conversation with another person, and someone walks by or interrupts and says something. Would it be illegal to keep the recording? </p>

<p>The prohibition applies to any "private communication". That term is defined <a href="https://laws-lois.justice.gc.ca/eng/acts/c-46/page-41.html#docCont" rel="nofollow noreferrer">here</a>, as</p>

<blockquote>
  <p>any oral communication, or any telecommunication, that is made by an
  originator who is in Canada or is intended by the originator to be
  received by a person who is in Canada and that is made under
  circumstances in which it is reasonable for the originator to expect
  that it will not be intercepted by any person other than the person
  intended by the originator to receive it, and includes any radio-based
  telephone communication that is treated electronically or otherwise
  for the purpose of preventing intelligible reception by any person
  other than the person intended by the originator to receive it</p>
</blockquote>

<p>Additionally, "intercept" is defined:</p>

<blockquote>
  <p>includes listen to, record or acquire a communication or acquire the
  substance, meaning or purport thereof</p>
</blockquote>

<p>If you talk loudly, it is not reasonable to expect that other people will not hear you, nor is it reasonable to expect people to not listen to things that they can hear. </p>

privacy canada recording