What about players who use house rules to change rules they don't like in an RPG. Are they still playing the game?
I think that I have to disagree with some on this one. I would say yes to this question, and for reasons I stated many pages back. To reiterate (and maybe clarify):
Is "Traveller" the rules? No, because we see many
very different rules systems (including Classic, GURPS, and T20) that are still considered "Traveller" because of some other quality that they all share in common.
Is "Traveller" then the OTU setting? No, because in any of these rules systems you can use non-OTU settings. Hiver-dominated space. Vulcan traders. Whatever.
What then makes "Traveller" different? If the OTU setting and rules are all there is, then Traverller would be a truly generic game. However, I think that many will agree that it is not, for many reasons. If this is the case, then there must be some third quality that defines what makes a game Traveller regardless of the rules used, or the setting used.
This is what I (and some others) were calling the "assumptions" or "essence" of the game: Jump drive and all that. These are in the "text" that some have mentioned as being separate from the rules. Well, I agree that they are separate, and would argue that this "text" is not less important, it is
more important. Personally I like how in GURPS Traveller the first thing they have to do is point out all the differences between Traveller SF and other SF games/stories that player might run into. Jump drives only, laser guns exist, but not such-and-such other SF guns, anti-grav occurs at an earlier tech level and is related with artificial gravity, etc. These things you can have in many different, non-OTU settings, but are what remain the only truly consistant thing between all versions of Traveller. If you take those away, then Traveller just becomes a series of often unrelated generic rules systems that come preferencially bundled with this OTU thing that you may or may not use. Like if GURPS came with a Star Trek "default" setting or somesuch.