Yes, I have been told wrong information to my face.
Yes, I have been told "gate one," when it is really gate 49. Yes, I have been told that my special meal is on board when it is not. Yes, I have been told they would hold the plane for my connecting flight, but they don't. Yes, I have been told that the flight is delayed due to ATC, when it is really because of crew shortage.

But I have found through all this that it is only on VERY rare ocassion that an agent purposefully lies. They should have better information, but unfortunately they don't. So we often complain that they are lying, when in truth, they just are in the dark.