Which is the exact problem that we're seeing, here. "Oh, I know, I'll just use a segment allocated to somebody else; it's not like they use it!" Aaand...whoops, they do.

I can't see anything about the 33.0.0.0/8 range being reserved

https://en.wikipedia.org/wiki/Reserved_IP_addresses

My personal favorites are 44.128.0.0/16, the explicitly unallocated test network for amateur packet radio to internet gateways, and 100.64.0.0/10, the address range for bidirectional carrier grade NAT.

Until they are and then everything breaks, which is basically what happened for 1.1.1.1.