I play professionally. My solution to settle any questions about what or how I play is simple: I turn off the accompaniment and just play piano every few songs or so. Naked piano is the ultimate statement regarding keyboard playing ability.

Also, I walk around to every table and greet everyone individually on my breaks, usually handing out song sheets so the customers can make requests (without driving me nuts by asking for things I don't know). Most people don't care at all how I make the music but some do and this one-on-one time is when I answer any questions about my keyboard or the technology I use.