I would not be happy with the examples stated in your first point, at least not as presented. That is, it "just so happens" that a helpful NPC is right there every time we need them? No, that stretches my suspension of disbelief far too much. Sometimes it can be the case, sure. But if the DM has actually done a sufficient job of justifying the situation at hand, then no "manipulation" is required.
That's my sticking point here. I work, very hard, to create well-reasoned, well-justified explanations for things.
<snip>
I try my best to avoid manipulating my players. I want them to do things purely because they enjoy them, not because they think I want them to do some specific thing or other.
OK. Do you regard the stuff that I described, that you don't do, as
railroading?
I put pieces down in anticipation of needing them at some nebulous potential future time. As an example, I had always intended that a certain NPC, Tenryu Shen, was a gold dragon in disguise. I left hints and subtle indications that something was Different about him, but it wasn't until the party had really proved themselves as heroes (and personally aided Shen with something) that he revealed his true nature and mission to them. We also established, early on, that Shen could heal physical, mental, and spiritual maladies that ordinary healing wouldn't affect, and this became very useful to the party later on. Would this count as "manipulating the backstory so that a pre-conceived series of events unfold[ed] in play"? As I said, I had always intended for him to be a gold dragon, one both aiding the party and requesting their aid in return.
Well, the only event described here is
that he reveals himself. Was that fore-ordained, by you as GM, to happen in a certain way? Did you manage backstory and outcomes to ensure it didn;t happen in a different way?
I had planned for him to be useful to the party under the specific conditions of that adventure
<snip>
through his aid and requests, I was able to send the party to important locations, reveal other backstory elements they had not yet seen, and in other ways "show my work" as it were. Is that "manipulating" or is it just...telling a story?
The revelation of other backstory elements raises the same questions as the revelation of
this NPC as a backstory element: Was that revelation fore-ordained, by you as GM, to happen in a certain way? Did you manage backstory and outcomes to ensure it didn't happen in a different way?
Sending the party to
important locations seems a different thing. Those are actions declared by the players for their PCs (at least I think they are - I don't think you mean the PCs were teleported to those locations). For me. this raises questions about who, at the table, established those goals for the players (and thereby their PCs), and how did those locations become important in relation to them? I think there are contexts in which answers to those questions exhibit something like railroading, but maybe of a different form from what I've described above: the GM determines outcomes and resultant scene-framing not by mechanical fudging, and not by backstory manipulation, but by social/metagame pressure on the players to declare particular actions.
@Campbell often posts about this phenomenon. It's the GM-side version of the railroading-by-players he's described: upthread he described players pressuring the GM to use their authority in a particular way; I'm now describing the GM pressuring the players to use their authority (ie over action declarations) a certain way.
I don't know, at your table, how those decisions about
what's important and
what actions the players declare for their PCs were made.
EDIT: I've just read
@Ovinomancer's post about this upthread. If the assumptions he is making about what happened at your table are correct, then he's right that it would be different from what I prefer in RPGing.