I ride in suburban territory, so I have to stop and start a lot; that probably qualifies as 'getting out of the saddle'. I have to ride 4 miles before I get to roads with so little traffic that I can ignore the stop signs and there are no lights. I can ride a lot farther without numbness and without getting out of the saddle on a Selle SMP TRK than I can on my B17 Carved.

IOW, pubic numbness can be prevented if one finds the right saddle. Alas, no saddle works well for everyone.