More than a year after Time Warner Cable somehow began suckering people into severely limiting their broadband usage to only 5GB/month — the equivalent of a few HD Netflix movies — for a mere $5 drop in monthly rates, Comcast has decided it wants in on this sucker’s bet too.

The folks at DSLReports write that consumers in the Fresno, CA, area are receiving promotional e-mails from Comcast about a new “Flexible-Data Option that “is specifically designed for casual or light Internet users who typically use 5 GB of data or less a month.”

Just like the TWC nonsense, the Comcast plan gives customers a $5 discount if they stay under 5GB/month. Cross that line… no discount. Additionally, you get charged an additional $1/GB of data used during that month.

Some might ask, “Why is this such a bad deal? After all, who wouldn’t want to save $5?”

Thing is, Comcast doesn’t officially cap broadband usage, but it will spank users who repeatedly go over 200-250GB in a month. So conservatively figuring that you could safely get away with 150GB of data a month on a $60 subscription, you’d be giving up access to more than 95% of that data for a paltry savings of only 8.3% on your monthly bill.

And under the Comcast plan, if you cross that 5GB threshold, you’ll actually be paying more than people with the ability to tap hundreds of gigabytes in a month.

So why on Earth are they doing this? Surely there can’t be that many people who don’t see this is a horrible deal. As DSLReports’ Karl Bode points out, this isn’t about making a lot of money off these particular people.

It’s also not about this much-shattered myth that the Internet is congested and ISPs desperately need users to chill out with all that Internetting, or that ISPs spend some ungodly amount bringing us our Hulu shows and HBO Go streams. In fact, studies show that it’s become cheaper and easier to deliver broadband to consumers, and the cable industry itself has admitted that congestion is not the reason for data caps.

It’s about establishing a foothold, however tenuous, in the market for metered broadband, so they can cash in on potentially billions of dollars in overage fees from customers who have gotten used to streaming much of the entertainment content that comes into their homes.

“So like the slowly boiled frog analogy, the cable operators hope they can slowly but surely get metered billing implemented if they just move glacially enough. The problem is that the option is so pathetic, very few are signing up for it.”

While it’s probably an inevitability that ISPs will ultimately switch to tiered plans, the only way to stave off that fate is for consumers to simply not buy into it. So please, if you hear some friend say “I don’t use the Internet that much; I’m thinking of saving a few bucks with this new plan from Comcast,” tell them to just say no.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.