Personally, I would NEVER touch a player, especially as a means to aid the player in completing a play that she is responsible for making herself. But that's just me...
One of the biggest arguments I had last season was on one of those "ball beats the runner, fielder misses the tag" type plays. I was the base umpire. A runner was advancing to third, the throw beat her by a mile, the fielder put her glove down in front of the base and was waiting, the runner was a dead duck, she slid in...and the glove/ball never touched her. She had slid right around and past the tag and was never touched. I called her safe.
The defensive coach just about lost it. He came out to me yelling that, "The ball beat the runner!". Yep, it sure did coach. But a tag was never applied.
His next argument was that "from his angle" it looked like the runner was out. From "his angle", in the first base dugout at least 100 feet from the play, I suppose it did. My angle was about six feet away from the play, looking straight at the runners foot, the glove and the base.
So he goes into the, "Can you ask your partner for help?", mode. Sorry, no. The plate umpire is 60 feet away and his view would have been blocked by the fielder. This is a judgment call and one that I was in perfect position to see. There's nothing to "ask my partner" about- unless you're just fishing for a second opinion because you didn't like the call.
Had I been the plate umpire, in a one umpire game, it would have been impossible to see the miss and probably would have looked like a good tag. As a practical matter, when working solo and it's impossible to get close to a play, "ball beats runner" can be a valid means to make your call, since it is the only thing you're going to be able to see.
There are long-running debates among umpires about these kinds of plays. Automatically calling the out when "the ball beats the runner" is known as making the "expected call". An "expected call" is one that probably should have been an out and probably looks like an out to everyone else viewing the play. It does have some validity in a one umpire game- imagine this same kind of play on a steal of second, where the plate umpire is going to be 80+ feet away from the play, and the near-miss would be impossible to see.
For me, if you are in position to see it and have a clear view of it, a missed tag is just that- the runner is safe. You can almost expect some grief from the defensive coach. But if the tag was clearly missed and you call the out, you should expect an equal amount of grief from the offensive side! Just call what you see- it's either a valid tag or not and the runner is either out or safe, just like any other play.