We've got a simple way to defeat this particular attack in Norway - the ballots are in the booth. You can take a dozen if you like.
Electoral workers inspect the booth regularly to make sure all parties' ballots are available.
If you cannot find a particular party's ballot, you are encouraged to take the remainder of another couple of ballots (So that you won't have to walk over to staff, asking them to provide more ballots for party X), leave the booth, bin the ballots and ask staff to refill the booth with all valid ballots.
Once you leave the booth (which is right in front of the electoral clerks), you head over to the desk with the voter register, your identity is confirmed against the register and then your (folded) ballot is stamped, immediately after which you put it in the ballot box. Only ballots with a stamp on them are counted, eliminating the risk that someone would (quite literally) go ballot stuffing by folding several ballots and trying to get them put in the ballot box; only the stamped one counts, anyway.
Electoral workers inspect the booth regularly to make sure all parties' ballots are available.
If you cannot find a particular party's ballot, you are encouraged to take the remainder of another couple of ballots (So that you won't have to walk over to staff, asking them to provide more ballots for party X), leave the booth, bin the ballots and ask staff to refill the booth with all valid ballots.
Once you leave the booth (which is right in front of the electoral clerks), you head over to the desk with the voter register, your identity is confirmed against the register and then your (folded) ballot is stamped, immediately after which you put it in the ballot box. Only ballots with a stamp on them are counted, eliminating the risk that someone would (quite literally) go ballot stuffing by folding several ballots and trying to get them put in the ballot box; only the stamped one counts, anyway.