I don't see how that would affect anything. If we assume that most people consume the most data in the evenings (streaming Netflix, etc), no matter the cap, you would see issues if bandwidth was an issue. If I'm downloading ISOs of Linux during the day at 100% everyday while people are at work, big deal, right? But, if everyone is streaming at the same time, if there was going to be an issue, it would happen if caps existed or not because at some point during the month you're going to have nearly all your customers with data to use.

> But, if everyone is streaming at the same time, if there was going to be an issue, it would happen if caps existed or not because at some point during the month you're going to have nearly all your customers with data to use.

It's a giant bucket of 'it depends'. If the CDN network serving the content has placed hardware within the ISPs network, it's likely a non-issue. This was a major issue before folks like Netflix started moving their CDNs closer to the customer. You might have a hard time finding the articles, but I recommend looking at the pissing match Level 3 and Verizon got into years back.

>it would happen if caps existed or not

I'm not convinced. You are essentially arguing that scarcity of a resource has no affect on consumption.

The way I've seen this handled in the UK (a while ago, but I think some ISPs still do it) is to have caps at certain times (either by having a limit or throttling bulk P2P downloads), but then allow unlimited downloads at other times, especially overnight