Most of the invalid ones are on there because people are advertising prefixes more specific than their ROA covers. 

Ie a 22-24 Roa and then advertising /28s on the exchange. Or more likely a 22-22 Roa and 24s on the exchange. 

It's as much about getting the range right as it is about the originating as and prefix

On Monday, January 6, 2014, Michael Fincham wrote:
On Mon, 6 Jan 2014 11:26:24 +1300, Dean Pemberton wrote:
> Anything that turns up as an "I" on this list, I'm going to be looking
> at pretty carefully before I prefer into the CARDIGAN network.

Cool. I think I see some of our prefixes in there, which is probably a
mistake :)

I'm travelling today but I'll be having a close look at this tomorrow
myself as well.

Michael Fincham
System Administrator, Unleash
Office: 0800 750 250