Actually, a simple google search for PlayOn.tv eula returns the EULA page for PlayOn.
And the EULA is included in the MediaMall install folder.
I tend to think conspiracy is where you look for it. I purchased a lifetime license back in 2009 for 19.99 (before there was a PlayOn Premium) and it still works exactly as advertised.
I purchased a PlayOn Premium license in 2010. I chose not to upgrade by Basic license as I figured I would continue to use it on a 2nd PC (which I do). Each time an update is released with bug fixes, both installations are updated.
I have never found anything deceptive about their marketing at all. Sure, I would have liked to have gotten HD for free, but I also understand that development costs money. The HD add-on is completely optional. I chose to add HD to my PlayLater license so I could record in HD but haven't added HD for PlayOn yet. The add-on for PlayLater only cost me 3.99. I think the add-on model is the fairest from a consumer perspective. If I had a slow PC, and was a new customer I wouldn't want to pay for a feature that I can't use.
That all said, since I purchased my lifetime Premium license in 2010, dozens of new channels have been added along with some very cool features that haven't cost me a thing. Things like Roku and Mobile support, PlayTo and Record To, the PlayOn Browser extension (PlayMark and PlayCast), not to mention the huge improvements made to MyMedia (which is still completely free, by the way).
I did do some searching around and found this from when I first purchased my Basic license (this is from 2009):
"What you get for buying a License
Your license will be valid forever for all patches and bug fixes for the current major version of PlayOn. All functionality and feature enhancements to PlayOn will be free for existing licensed installations, unless a new major version is released, at which point a new license may be required to access newer functionality."
I get why some might be upset...Heck, I'd always rather get something free vs. paying for it...but deceptive and greedy? I don't think so.