The Japanese, at the very least.
Sorry.
Six years past our supreme court annulled an entire election based on irregularities that happened during the counting of the mail-in ballots. The irregularities amounted to less than the total lead of the winning candidate, so even if they all had been manipulated in favor of the winner of the election and all of them would have gone to the other candidate instead (which was highly unlikely with an almost even 50:50 split), he would still have won.
What kind of irregularities you might ask? Why, they were counted on Election-Sunday, while election regulations state they must be counted on the Monday after. Which some smaller districts opted not to do because there the counters have actual day jobs and aren't full time politicians. All the counts were signed off by members of the losing party's candidate, and the party elected to throw the signees stating that regulations were upheld under the bus and file for annulment (causing cases to be opened against people whose 'crime' was counting votes earlier than allowed, with full knowledge of the parties in question and auditors of every party present).
Early counting of mail-in ballots has always been done, and every party knew it, and everyone was happy with the way it worked, until it became convenient to have a close election repeated. The voters proceeded to thank them for having to vote again.
I know, we're roleplaying Bruno here.