I just finished ccw 14hr class yesterday. I was told that if it is seen by others whether openly or the imprint through a shirt, or the wind blows your shirt up for a split second and someone sees it, they might call it in and they can say whatever they want to 911 and the cops will come with force. For example someone might say you were waiving the gun around like a homicidal maniac, even tho you weren't.. Who will they believe? You can definitely get in trouble. More than likely they won't do that, but if they do.. you're screwed. Here in az a permit is no longer required but like my brother I opted to take the course anyways to get the permit for 3 basic reasons;
1. I have the advantage vs open carry(they don't know I have a gun)
2. Less likely chance of going to jail just because I went through the training and am now permitted by law to carry and conceal.
3. Less likely chance of getting harassed by public and cops. For example if I get pulled over for any reason and I tell the cop immediately, "I am a ccw permit holder and I have a concealed firearm on my right hip." He will more than likely be reasonable and politely ask me to step out so he can remove it. He may not even do anything except say keep your hands on the wheel. Versus me not having a permit and just saying I have a concealed weapon. Therefore he would be more prone to being suspicious and may even pull his gun on you and start yelling, etc..
BUT... I'm not fully aware of all the laws yet and am currently beginning the process of extensive research in these matters, but i.m.o. I now believe it makes total sense to never show your weapons as it can be misinterpreted or cause panic, and people tend to over react.
So its mostly up to you or any laws in your state. Basically, do you want to risk going to jail unless its absolutely necessary in that life threatening situation where you would be justified in either defensively displaying your weapons, or shooting to protect your own life.
As far as losing your permit if you open carry.. I haven't a clue. Probably not unless you are actually convicted of that crime which the person lied about that saw your gun and freaked..