Teleport gym take down.....
So I just watched a Valor player take down a gym I just cleared within seconds of me clearing it. Then teleported across the lake to take down another gym I had previously cleared a few minutes ago.
Can't Niantic put a lock out on gyms where if you are gym A you cannot battle gym B if the time it took you to arrive to gym B from gym A is less than egg hatching speeds?
This would solve the teleporting or at least aggravate the spoofers because they will have to teleported in short distances until they get to their destination or risk getting soft banded for 12 hours or something.

Answers
Can't Niantic put a lock out on gyms where if you are gym A you cannot battle gym B if the time it took you to arrive to gym B from gym A is less than egg hatching speeds?
==> Impossible. Suppose the egg hatching speed is 10kph. So, if a player takes down a gyms in Los Angeles then travels to New York by plane, he has to wait for 2 weeks to play ;)
A travel-time technique similar to the technique used in Google Maps (where one by using the quickest travel options available including flight, car, train would hopefully avoid the problem you bring up).
The identified point-to-point travel times could be calculated in a one-off operation and be retained in a database to eliminate the need for real-time travel time calculation.
From LA to NY is about 6 hours. They can put in a distance and fastest via method available.
Realistic speeds. Right now if I WIFI drift from one city block to another, I'm unable to spin pokestops and everything runs away after the first ball. The can implement the same thing just for longer periods.
I wonder if anyone has ever gotten banned from a report/ticket? In our town, there is a gps spoofer taking down gyms (with multiple bought lv30-34 bot-accounts) and several people have made all kinds of tickets to no response (about gps spoofing, bot accounts, insulting player nicknames, multiple accounts, stacking 10 bot-account-3000cp-snorlaxes at same gym while gps spoofing ...). Finally it seems the guy just got bored tapping gym battles at home, but there are still those accounts to be seen at gyms.
There's also no point to play the game that have so many cheaters around but you aren't. Since the developer don't even care to stop this behavior, why do you have to pretend to be a good guy?.
Soon this game will full of spoofers bcuz the ppl who play normally will quit the game just think about it. The game is not ruinning itself but the players.
Most spoofers also use a joystick that allows them to “walk” any amount of meters they want per joystick tap (I have seen them do this on YouTube). With a short distance as shown in your image, they could easily “walk” across the water with a few taps on the joystick, without ever even setting off the “you’re going to fast” alert and just take the gym. There is nothing we can do about this unfortunately.