According to Consumerist, Verizon is in fact letting ports saturate:
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consumerist.com/2014/02/ ··· service/quote:
Cogent Communications, one of Netflixs largest bandwidth vendors, said last summer that Verizon had previously opened up new ports to ease or prevent congestion when traffic hit around 50% capacity, but that the telecom giant had recently begun letting some ports reach 100% capacity without acting.
I don't know their sources, but they are speaking as if it were fact.