I do not see a scrubbed background. Smeared, yes, as what the SMEAR tool creates, but no scrubbing. The artist would have a lot of white streaks remaining. It owlud be so much easier to use the STAMP or BANDAID tool.
It looks more like an overlay of the background given that the other folds are missing.
Hawaii does not mail out these certificates in manila envelopes, but in regular #10 envelopes. They certainly would not fold it only once.
-PJ