Dunno about the real impact of having postal votes made by public mailbox labelled in such a manner, but I do think the way the US does elections is procedurally stupid.
The variable use among states of ballot-marking devices and voting machines is one example of this.
That the powers of the Federal Election Commission don't extend to consistent nationwide electoral administration and that this is managed by officials and agencies in each state is another.
These things hardly determine the presence or absence of civilisation but, as with many aspects of US parliamentary democracy—some more of which we're quite likely to see if this poll results in further constitutional shenanigans—it's pretty far from perfect.
