Verizon S3 native Wifi tethering without mobile data

I'd like to use the native Wifi tethering on a rooted, stock ROM Verizon S3 WITHOUT the need for any mobile data. I'll be using it only to allow connected devices to access content that's already on the phone. It's a custom application not for any sort of public distribution. This isn't a problem on AT&T S3s (or other phones), I've done that successfully, the phone just lets it happen. But the Verizon phone won't let me do it--without a plan that includes tethering the phone shuts down the hotspot after a few seconds with the "you need to go buy a tethering plan" dialog. I'd like to use native tethering instead of another app if possible to keep my code simple and uniform across phone models, and avoid a dependency on non-free third party apps.

Anyone have an idea how I can convince the phone to leave a native non-mobile-connected hotspot up, without a tethering plan?

Thanks!
John