1.5 TB is one, heck of a pay load to be pushing. My concern wouldn't be the bandwidth being currently used, but how much bandwidth per gig it's costing CableOne, unless they own their backbone, in which case, they've got nothing to complain about and you shouldn't be concerned.
Chances are you probably didn't spoil anyone in the bunch. What tier are you on? I'm on 10 meg here, regularly pushing close to 200 GB per month now. I seriously doubt I'm disturbing anyone on my node; whenever I had to call tech support, they were always telling me how quiet my node is, and that was before my area was even upgraded to DOCSIS 3.. so now there's even MORE bandwidth available to everyone in my neighborhood. What's the problem? And why did they get rid of the 10 meg tier in favor of 5 meg, which is now the same price as 10 meg was? Backwards trend much? I couldn't stand being on 5 meg for long. I would get throttled almost every single day; I AM NOT going to work around some stupid schedule because your AUP assumes we're all on overloaded nodes, which, by the way, is more your fault than anything. All ISPs need to be prepared for traffic increases; gradually tweaking their systems, splitting nodes when needed, etc. Using caps and clever marketing are band aid fixes. Customers are becoming more aware and many of us will not stand for it.
My thought on CableOne's new tier pricing still stands; it's a money grab. They want to look better among the other ISPs by having higher speeds, but severely limiting them with low caps. This would imply that CableOne really doesn't have the bandwidth for today's generation of internet users and/or they really just want the money. They think we're all still interested in the garbage known as TV, because let me tell ya, I enjoy watching that reality garbage and I need my sports fix.
Most of what I watch is online-only based exclusives and Netflix content. CableOne's channel selection has always been mediocre and their on-demand content has nothing of interest to me. My usage is typical of a residential network with multiple internet-savvy users. I don't run a server, I just use the internet for all of my media needs.