This topic was discussed a little bit
here,
here, and
hereBasically, some games implement checks that read the value stored at 0x80000300 and display a screen saying the cartridge was not designed for this system. Some games have a check to block the console but don't display an error message (as an example - Majora's Mask JP has a check, doesn't display an error message, but hangs at a black screen after the Nintendo 64 logo if you try and run it in 50 hz mode).
There's a Brazilian Portuguese translation for Majora's Mask that uses the N64 PAL rom, and I've just recently broken on the PAL Rev A rom. You can find the ported translation here:
MM (T-BR)(Projeto BR)(1.1)(Aroenai).zip (use the "Legend of Zelda, The - Majora's Mask (Europe) (En,Fr,De,Es) (Rev A).z64" Big Endian rom)
Now, while I haven't been successful with the Australian version of Beetle Adventure Racing (HSV Adventure Racing), I think I've narrowed down the location of the check to 0x8005ADB4. Maybe someone else can trace the asm that reads from 0x80000300 and figure out what it's doing?