My personal experience with UCEPROTECT was that they had blacklisted 2 or 3 IPs in my /24 that were not routed to anything, nor had they ever been routed to anything, a fresh new block from RIPE NCC too.
Of course they offered to unblacklist them in exchange for payment, or wait.
Waited 2 weeks and they dropped off. I've yet to hear about anyone using their DNSBL for anything serious in 2020/2021/2022
I only knew about the listings
because a monitoring service emailed me about it.
While I personally don't use UCE (and personally think that they're not good at what they're doing), unless you've get that IP range before 2012, I doubt it's a new one. Many spammers do often exploit RIPE's unallocated IPs for their spamming operations (either using BGP hijacking or just asking RIPE nicely for a range), which unfortunately is a perennial problem.
Of course they offered to unblacklist them in exchange for payment, or wait.
Waited 2 weeks and they dropped off. I've yet to hear about anyone using their DNSBL for anything serious in 2020/2021/2022
I only knew about the listings because a monitoring service emailed me about it.