You are absolutely right, there is actually a whole panel of different techniques that aim at getting you accept offers you would not accept straight on.
I believe as a consumer it is important to be aware of those different manipulation techniques so you can step back and take a rational decision.
For example in case of call for sale, it should trigger an alarm telling you to walk away. If you have a high interest in the product and want to call anyway, make sure to know what price you are willing to pay BEFORE calling and do not commit to anything during the call.