If it's in a public setting, you cannot be asked o leave. If the police confront you and remove you, you are able to get damages as long as damages could be proven.
A public place can sometimes be private if the event space is rented, for example a gun show at a city/county owned building or property.
Also, You only a need a LTCH if you are carrying a handgun. For a long arm, there is no license needed (or issued).
For example at a tea party rally 2 years ago valpo PD asked for my LTCH and another persons over our openly carried handguns. None of them asked the AR carriers for one
The only restriction would be the new restriction on open carrying at a public meeting for a county council or city council meeting that was included in the new preemption bill (SB292).