I'm doing a prototype layout for an intermediate amp using the 5605. The data sheet for the ADL5605 specifies NC for pins 5,6,7,8,13,14,15,16. Yet the images of the dev board shows these as connected to the upper ground plane and the vias underneath the paddle. Due to constraints of the design I am working on it would be most useful to be able to place a 2.5mm solid copper bar underneath the part passing through the area occupied by the vias in the dev board, effecting the low impedance return path as well as effective heatsinking. Doing this while only contacting the paddle is possible, but it would be significantly easier to place it in a manner that also contacts these NC pins.
What would the effect of grounding these pins be?