How risky is it to write a AU card for a subbed box?
are the cc peeps able to tell if i use a au card? does he box tell them what i am watching?
Yes, they can potentially tell !
One of the things a subbed box does on a regular basis, via its talkback channel, is send information to VM regarding your tier map. If you have tiers you shouldn't or the min/max (or even dates) are wrong then VM can easily see the differences (assuming they actually bother which is unknown)