Note, "a consistent set of rulings from a good DM" is unlikely to ever get challenged by players aren't they? I mean, if the DM is good and is making consistent rulings, why would the players feel the need to challenge them?
Because the player does not like the ruling?
I'll give an example. I was running a Champions game. The bad guys were very skilled and smart. I had a desolidified guy put a bomb into the jet engine of the spaceship that the PCs were going to use. He went deep into the bowels of the engine, let the bomb solidify, and then walked away. He did this hours before the PCs even got there. There was no way without some type of advanced powers (X-ray vision, super sense of smell, etc.) were going to find the bomb. The entire scenario was set up by a genius villain who took all types of contingencies into account and worked to ensure that the heroes were in the dark.
So one player with a good Perception (forget the name of the skill in Champions) decided to search the spaceship. No special powers and he was searching a decent sized space ship for a few minutes before takeoff. I told him that he did not find anything (because there was nothing to find with his abilities).
When the bomb went off, the player went ballistic. He had asked to search and I had not even given him a roll (the reason for that is if he would have rolled great, I would have either had to modify the scenario, or he would have been even more ticked off). Some players are immature and just do not like some things that the DM does. A different player would have accepted the situation/adjudication without batting an eye.
If you are being challenged by your players on rulings, it might be time to step back and do a bit of self examination on just how good of a DM you really are.
That doesn't logically follow. Someone could be a great DM and be challenged by his players because they are disruptive players. One has to not just wonder about the DM, but also has to wonder about the players. Are they rules lawyers? Are they disruptive? Are they people who typically get their way in an FRPG? Or are they just the type of people who like discussing every little detail to the nth degree, including DM adjudications?
I suspect that some players who often question DM adjudications are just opinionated people who cannot keep their mouths shut on unimportant stuff.
IOW, most players are not challenging rules because they are bad players, or want to gain unfair advantages or anything nefarious like that. I truly believe that players are earnestly trying to make the game better for everyone at the table, just like the DM is. We all have the same goal, so, why not work together towards that goal, rather than resting all the responsibility and power in the hands of one person. Many heads are typically better than one.
I think that people are people. Good ones. Bad ones. And you find this in nearly every group of people, even if they are your friends.
When it comes to adjudicating, many heads are not typically better than one. An experienced DM is typically better at adjudicating than a player who has rarely or never been a DM. No doubt, a player can and often does come up with a good idea. But it's the responsibility of the DM to have the final word and either go with those ideas or not, not the players.
To be fair, there are bad players out there too. But, that's a separate issue. I'm presuming good faith on everyone's part, player and DM alike. There's been numerous posts in this thread alone where that presumption is not shared by DM's.
It's not a separate issue. It's often the root cause of problems at tables. It's usually not the DM, it's usually one or more disruptive players.
Many of us have had bad experiences with subpar DMs, but the simple solution to that is to move on. It's sometimes harder to ask problem players to leave than to leave yourself, especially if those players are close friends.
