We number boxes, no colouring in for us!
In the UK voting is usually with either an X in the appropriate box, or numbers in boxes. I suspect if a 1 and 7 were truly so badly written that nobody could unambiguously tell them apart the ballot paper would be considered spoiled.
Voting machines seem fine in theory but it's hard to see how they can be above suspicion of enabling vote rigging. I've read a few reports of people who claimed to have tried to vote for Donald Trump only to find their ballot was cast for Hillary Clinton. Assuming they are true (and given the way social media etc has a tendency to pick up just about anything regardless of accuracy they may not be), it causes a lot of concern.
Ignoring the direction of the change allegedly made in the voting, if the machine is misallocating a vote the entire election is immediately suspect. Likewise if, as officials allegedly claimed, the voter merely operated the machine incorrectly it also renders the election highly suspect simply because if the machines are designed such that people could accidentally vote for the wrong candidate it suggests incredibly poor user interface design, or a lack of a final check that should be a matter of routine. I recall back in the 2000 Bush-Gore election there were rumblings about the process being confusing in ways that could have led people who wanted to vote for Al Gore accidentally voting for George Bush.
The actual direction of the change allegedly made is potentially of secondary concern simply because if the problem is incorrect usage by the voter it's not unreasonable to assume that some people who intended to vote for Clinton may have inadvertently voted for Trump. On the other hand if it could be demonstrated that a certain percentage of votes for Trump were assigned to Clinton by design then essentially it means the entire election has to be invalidated because it's impossible to know how many Clinton votes were digitally stolen from Trump (and, of course, if it could be shown that votes for Clinton were being assigned to Trump the same would apply).
