Its not the hole in the pulltab that makes it ring up in the gold range. Gold and Ammonium have similar properties and are to close for the metal detector to separate. Metal detectors operate within a RANGE of chemical/metallic properties. Right now I know of no detector that can without a doubt distinguish between the 2 since since the metallic composition of gold changes with the karat value. 24K is pure, but 18k, 14k, 10k ........ all have mixtures of different alloys added. Aluminium also has different components added depending on the days run. These additives make the amount of metal/alloy go further or become stronger. Coins are all made from pretty much the same recipe with the exception of the Zinc pennies. One day it may have more zinc properties and the next may have more copper properties. Metal detectors and only take an educated guess of which it may be.
Pull tabs, aluminum foil, gold, & nickels are all in the same VDI range.
What can sometimes help you to avoid excessive digs is to look at your depth meter first. If it is deep, it could be an old nickel. That will help cut back on retrieving all that unwanted foil and gold. lol