No problem
That was a short post from my mobile just because I was worried what they would say and wanted to update the OP asap.
Home again now...
I tested it 2x
that was CLE - Washington DC - they just let me, i was "will call" and showed up and said i missed my bus due to flight issues and they printed my original ticket so the ticket and bag check slips had my original time, bus driver did not care/ does not as long as you have a ticket. Only time was a issue was because I was "will call" and had to have them print it up.
Then yesterday from San Antonio I missed the bus again, and same thing, took next one. no problem no fee. The bus was the worst though (poor driver/rude/dirty/loud), I have only been on GLI this was Americanos. I would probabbly have waited for a GLI later if I had known they were not all GLI.