TCP and UDP Port 0 - Should an ISP or ITP Block it?

I think that the subject of the e-mail is very self-explanatory. With some analysis of what is running over our network, ISP or ITP, we will be able to see some TCP/UDP(mostly UDP) packets with source or destination to port 0. I can think of a genuine use of it. (Maybe someone cloud help me see what I'm not seen.) So I have two questions: a) Should an ISP block that Kind of traffic? (like anti-spoofing on BNG/B-RAS) b) Should a Transit Provider block that Kind of traffic? -- Douglas Fernando Fischer Engº de Controle e Automação