> "Unlimited usage for a flat, monthly fee" this would suggest
The weasely way around that, used certainly by UK ISPs in defending their use of the word "unlimited" is that you have unlimited access (24/7/365.25) rather than unlimited bandwidth use. While they meant "use as much bandwidth as you like" they never specifically said that, so they no claim they didn't mean that and noone can proove otherwise. The claim is that it is unlimited compared to dial-up days when ISPs had to maintain a massive rack of modems so, particularly for cheap or free-call ISPs, you would have limits like "up to X hours per day" and "no session longer than X hours".
So while it can be said to be deceptive and dishonest, it doesn't actually breach truth-in-advertising laws (at least over here).
There is an ISP over here (Sky) making a big thing of actually offering "use as much bandwidth as you can", though there is more weaseling there - there is heavy protocol level traffic shaping which limitis how much you can actually use and there is still a "fair use policy" which is sufficiently vague that it could mean anything.
I pay good money for what is essentially a business account. It has a 300G limit, but that can carry over from month to month and if I go over (unlikely) and don't have any carry-over left from last month they'll just charge me a known rate for the extra (charging by byte, not in much larger blocks). That is the only way (here at least) you can get a proper, unfiltered, unshaped, un-anything-you-didn't-ask-for-ed connection. Pay for what you want and you have a chance of getting what you pay for.
I pay about £20/month for BE Unlimited and routinely burn through 500gb-1TB a month (like TFA I use multiple lossless codecs for media I've bought or produced, as well as using a series of permanently nailed up VPN connections for various things) without any problems. YMMV, but it's fine over here.
Yeah, I should have mentioned Be... I used them myself until a couple of weeks ago. I never pulled your 500G+ but I can say I never noticed any shaping or other artificial limits or significant congestion on those occasions I did pull many Gbs around in one go).
I've shifted over to an FTTC provider - 10Mbit upstream is nice to have especially coupled with as many IPv4 addresses as you can justify for nowt extra (only a /29 for me (all I need) but people get more - you just have to ask and promise to follow RIPE's allocation & use rules) and native IPv6, the upstream is unmetered like Be but not downstream.
Rumour has it Be will need some significant infrastructure updates to keep with that policy when they join the FTTC roll-out unless they make their FTTC based products uncompetitively expensive which they may not be able to afford to do.
The reason I picked Sky is that they are advertising the "unlimited" thing pretty aggressively on TV right now, and I know their network is shaped to buggery as are any other ISPs other than Be (that I know of) who offer "unlimited".
For people interested in Be (I'm happy to recommend them, even though I can no longer get a "referral" discount for doing so!) nip over to https://www.bethere.co.uk/
The weasely way around that, used certainly by UK ISPs in defending their use of the word "unlimited" is that you have unlimited access (24/7/365.25) rather than unlimited bandwidth use. While they meant "use as much bandwidth as you like" they never specifically said that, so they no claim they didn't mean that and noone can proove otherwise. The claim is that it is unlimited compared to dial-up days when ISPs had to maintain a massive rack of modems so, particularly for cheap or free-call ISPs, you would have limits like "up to X hours per day" and "no session longer than X hours".
So while it can be said to be deceptive and dishonest, it doesn't actually breach truth-in-advertising laws (at least over here).
There is an ISP over here (Sky) making a big thing of actually offering "use as much bandwidth as you can", though there is more weaseling there - there is heavy protocol level traffic shaping which limitis how much you can actually use and there is still a "fair use policy" which is sufficiently vague that it could mean anything.
I pay good money for what is essentially a business account. It has a 300G limit, but that can carry over from month to month and if I go over (unlikely) and don't have any carry-over left from last month they'll just charge me a known rate for the extra (charging by byte, not in much larger blocks). That is the only way (here at least) you can get a proper, unfiltered, unshaped, un-anything-you-didn't-ask-for-ed connection. Pay for what you want and you have a chance of getting what you pay for.