BCP 38 is nowhere near usual. Lots of networks, including some very problematic big ones (cough Hurricane Electric cough), do not implement it as a matter of course. The AWS Route53 hijack last month which resulted in downtime for a number of sites plus a six figure coin theft could have been prevented by adequate filtering.
They may also not even have a duty of care in the first place, as to the truth of any metadata they're passing on. As a sibling comment pointed out, it's not as if there are laws for this.
On an airgapped lab it is bad practice. Same -though DNS related- with using *.local as a LAN TLD
An edge router is not one of these cases though.
Some of them were made more lenient because just as Microsoft finally stopped encouraging this nonsense, the Kubernetes people picked it up from ancient Windows Server folklore and apparently decided to make it web-scale.
It's been a while, but I can't count the number of times that I've seen that.
What's enormous about an IPv4 /12? :)
When the German army requested an allocation of IPv6 address space, they were given a /28, but complained that 2^100 IPs is not enough for them and they actually need a /22.
Did they want each bullet to have a /64?
I get the impulse to say "you used it wrong, now it's broken", but we didn't get to a functioning worldwide internet with that attitude. We got here by observing what people were actually doing and coming to a consensus view on what to break and what to carefully tread around (you know, UX). This is an obvious example of the latter and the fact that APNIC let CF use this space for a production platform in the name of breaking shit is frankly disqualifying (in terms of their overall trustworthiness as curators of essential IN infrastructure).
However, the RFC1918 IP ranges have existed for a very, very long time, as have the standard documentation/example IP ranges which Cisco, Juniper and others have been using in their training and example publications since 1995 or so. People have had more than twenty years to number their internal networks into the ranges that, also by consensus, the global internet community has decided to make non-globally-routable (192.168, 10.x, 172.16, etc). RFC1918 was published 22 years ago so there is really no excuse.
If you are using 1/8 in the year 2018 for your own internal production traffic, you are wrong and should feel bad. IANA and APNIC (and APNIC's contracted partner, Cloudflare) should be able to begin using ranges as granular as an individual /24 within this /8 on the public Internet without worrying that people who have misconfigured their shit will have a broken experience. It will take time for people to move their misconfigured erroneous configurations into normal RFC1918 IP space, but it will happen eventually. Or maybe not, if v6 adoption speeds up this becomes irrelevant.
It is/was not uncommon either. It was never a concern since it wasn't allocated. It being a concern is a very recent phenomenon.
Yeah, no. It sounds like you don't really know the history of that block. Or maybe you missed the part where I said it was used as a loopback address. Maybe both.
126.96.36.199/8 was unallocated and was also part of many peoples bogon filters at their edges.