Is there something confusing about this???
D. The carrying of a concealed or unconcealed firearm by a person who has been issued a handgun license on property that has signs prohibiting the carrying of firearms shall not be deemed a criminal act but may subject the person to being denied entrance onto the property or removed from the property. If the person refuses to leave the property and a peace officer is summoned, the person may be issued a citation for an amount not to exceed Two Hundred Fifty Dollars ($250.00).
That's it. No arrest, a ticket for trespassing IF and ONLY IF they see it AND ask you to leave AND you refuse (stupid) AND an LEO is summoned and tickets you.
So... ignore, conceal, and if noticed and ASKED to leave, then do so. That's it. Nothing illegal about it, and they cannot prohibit weapons in your car in a parking lot regardless - per state law.
You can be arrested for trespassing. Many of the citations people are issued on a daily basis are in lieu of arrest. I deal with trespassers quite often at work. None for this exact reason, however I can tell you about the general police response. If the person trespassing is not making a fool of themselves generally they will be sent on their way with a stern warning from the police. If they are a habitual trespasser they usually end up being cited for trespassing. If they are belligerent or we have multiple documented trespass violations from them they may go to jail. It is not common but not really uncommon for people to be arrested for trespassing.