Another error in the rules.
BIDDING ZERO
"If more than four cards are dealt to each player:
Player bids zero and does not take any tricks, the player has made his/her bid correctly. The players scores 20 points.
This should be 25 points, not 20 points
Mea Culpa

What happens in a 6 person Camelot game if you bid zero on the last hand, and you take the trick with the Holy Grail, under the Excalibur. The trick doesn't count against you, so you make your zero bid, scoring 30 points. Do you also get the 20 for Holy Grail for a total of 50 points??