Always assume when you’re put on hold that the other person can still hear you.

lifepro-tips:

I work at a towing company, sometimes when people call in with damage
claims complaints etc. we just mute the call and listen for a minute or
two, usually someone slips up to a friend what ACTUALLY happened and we
just blow them off/ give them the run around from there.
Most calling services listen in while your on hold for training. So mute
your side if your going to say something you wouldn’t want the person
you trying get a hold of to know.

Source: reddit.com/r/LifeProTips