@Awad,
That's nice that you are good guy and is doing a lot to save yourself from such things. for you it seems to be right as you paid for it.
However, those who are taking out phones from container saying that it's for inspection purposes. They are doing wrong thing. If they want to inspect, they can put it back after inspection. If they aren't returning it, this is simply not right.
However, it's their beleif and their choice.
Best of luck for the sale! you are very right about keeping expensive phones.