[TnGOP]

I haven't seen the postage due photo but in our package processing center there are machines that will scan the barcode, weigh the package, and reject packages for postage due. But these packages had no barcodes when they reached the sort center. We have stuff that will easily read those address labels, but I don't think they scan for stamps and calculate the postage paid, so they wouldn't necessarily be rejected for postage due.

In fact these would probably only be caught by an alert employee that happened to see them all together. Were they even dropped at the same location? I guess we'll know more soon.

[mom aka the evil dictator]

The machines will only catch ePostage labels that have the wrong amount on them. They will not catch something with flats postage that should actually be a package either. These packages had stamps on them so would have had to be caught by whomever emptied the collection box or on the receiving end.
You are correct that an alert person would be the one to catch them. I am not even sure that they all came through the mail. I seriously doubt we could have delivered to so many diverse zip codes with them arriving on the same day.