This means, if you ever have a PayPal-froze-my-account issue, you are guilty of Fraud, and thus they take back all your bought (Erm, rented?) games.
This is something I do not like and that always gnaws at me about the platform. Especially combined with their very poor customer support. ( Approaching Google-level of user hostility )
- need to be single-user admin with saved password
- didn't know that before? tough! you're locked out from all games including DRM-free ones
- happened again and still can't get offline mode? tough!
- support limits how big a message you can send so I couldn't send complete info (not that they looked)
- support promotes racial hatred, closing issue with poor English and telling me I didn't do what I did.
- follow up support also closed.
- considered small claims court but was convinced it really wasn't worth it.
lesson learned: There is no such thing as "friendly" DRM. When the system decides you are wrong, there is no recourse
 Unless you're a famous blogger, have a personal contact or other out-of-band means unavailable to the masses.
In my experience the steam client is physically painful to use (unpausable downloads, cache verifications, slow startup, unresponsive store). It's not as bad as iTunes, but it's getting there.
Is there an easy way to filter games by this criteria on Steam itself?
Yes, that is the case case with the DRM free Steam games I have played. I guess that this is common among indie games at Steam, but I have not really looked into it.
> Is there an easy way to filter games by this criteria on Steam itself?
Do not think so. I do not think Valve want to dissuade developers to use their DRM.
3rd-party DRM: SecuROM™
4 machine activation limit
Yeah, they get more by shoehorning people into Steam than they would lose from not selling DRM-free versions.
There may have been a point to stop this from growing into what it's become early on... But it's too far gone to be broken free of save a major scandal. And even then, it'd probably take a few. It's just by far and large a non-invasive tool. They've worked out many kinks.
I'm not saying it's perfect, nor am I saying we should be happy with it. But it's avoided the major problems most other DRM efforts see in "making things more difficult for legit users than pirates". I haven't had any issues with any aspects in years.
I understand that Valve can be already too involved with game producing companies which still have backwards thinking that DRM is a must. But Valve can start pushing them to drop it, instead of being passive.