For a ball to be in, it must actually touch the line. Being above a portion of the line at point of maximum impact is not sufficient.
As you rightly mention, the rules are fairly clear. From the 2021 Friend at Court document:
If a ball touches a line, it is regarded as touching the court bounded by that line.
Similarly from your source (though I don't ...
The amount of time it takes to review is somewhat of a pain point with VAR. Soccer involves many people, and their interaction with each others. To review you need to look at a number of angles, and interactions are open to interpretation.
In tennis use of Hawk Eye is automatic as the only need to be tracked is the ball. But in soccer you need to take a look ...
It's hard to prove a negative, but neither the Laws, nor the Instructions to Technical Officials, nor the BWF umpire manuals mention any right of the umpire to refuse a challenge.
The only limitation on challenges follows from §5.8.5 ITTO:
(...) The player must clearly say ‘Challenge’ to the Umpire and/or
make a clear signal by raising the hand. Any such ...
It will count towards the innings limit of reviews for that team.
For example, the ICC test match playing conditions state in paragraph 3.6.5,
... A Player Review categorised as ‘Unsuccessful’ shall not be reinstated if, despite any technical failures, the correct decision could still have been made using the other available technology. Similarly, ...
Cricket adopted the "Third Umpire" in Test Matches in 1992.
The Third Umpire was an individual who reviewed a video replay of a line decision (Run Out, Stumped or Boundary). In later years, catches were also reviewed.
This Umpire was only invoked if one of the two on-pitch umpires called for a review.
They're not using lines judges at the 2021 Australian Open this year due to the pandemic, an effort to reduce the number of people involved in the matches and the tournament in general. We saw the same thing in some tournaments late last year post Covid. All line calls are done by Hawk Eye in real time, on all courts of the tournament. Like usual when the ...