Unless they also demand that you film yourself continuously up to putting the envelope in a mailbox, they can't be sure you actually mailed the ballot or that y

Unless they also demand that you film yourself continuously up to putting the envelope in a mailbox, they can't be sure you actually mailed the ballot or that you didn't invalidate the result later. This would risk exposing yourself, and in turn, the intimidator. But if only one ballot is mailed per citizen, they can be reasonably sure you didn't vote for the competition.