Hi Owen, Randy, Job and other NANOGers, 

I surely agree with you all that we shouldn't expect discarding of ROA-unknown `anytime soon' (or ever?). But I have a question: what about discarding ROA-unknowns for very large prefixes (say, /12), or for superprefixes of prefixes with announced ROAs? Or at least, for superprefixes of prefixes with ROA to AS 0?

For motivation, consider the `superprefix hijack attack'. Operator has prefix 1.2.4/22, but announce only 1.2.5/24 and 1.2.6/24, with appropriate ROAs. To avoid abuse of 1.2.4/24 and 1.2.7/24, they also make a ROA for 1.2.4/22 with AS 0. Attacker now announces 1.2.0/20, and uses IPs in 1.2.4/24 and 1.2.7/24 to send spam etc.. We introduced this threat and analyzed it in our ROV++ paper, btw (NDSS'21 I think - available online too of course). 

So: would it be conceivable that operators will block such 1.2.0/20  - since it's too large a prefix without ROA and in particular includes sub-prefixes with ROA, esp. ROA to AS 0?