Windproof Sign Holder

I've done a handful of markets recently and all of them have been plagued by the sudden gusts of wind which would knock over all of my signs. This sign holder has small notches at the base where the bottom of the sign will sit. As this is lower than the rest of the base the bottom of the sign can't slip backwards, therefore preventing falls.I will be testing the design this weekend outdoors but it had currently withstood me poking the sign quite forcefully. As always feedback is more than welcome and if you find this design useful please consider boosting.