In another thread MetalliC mentioned that there's a flag in the NAOMI ROM header that specifies if the game will allow booting into an unsupported video mode. I've booted every Net-Bootable game in 31K mode so I started playing around in 15K mode.
Airline Pilots and Sega Strike Fighter will both refuse to boot if the NAOMI is in 15K mode. Also Wave Race GP will ignore the dip setting and boot into 31K mode even if the jumper is set to 15K mode.