Sure, but just because the system says stop at some point doesn't mean it can't be pushing before that.
It puts a hard stop at how much you can push,
It's not easy to decide when something is too much or not, the system is in essence already working as a referee.
There are so many ways you can obfuscate a push so that it's near impossible to track.
If I want I can push as much as I like without you seeing any proof of it ever, a plain old example I have seen pushers do is removing the road connection from a wonder unless they are pushing. this means you have seconds to detect a push making it pretty much invisible. expecially since you need to see something many times over. an incident can't be called a push.
This system doesnt care, it just tells that you cannot gain more KP from wonders / players than your wonders/players give away.
You can use many different accounts (most extreme example I have seen was more than 150 accounts), use multiple IP adresses and computers, keep the wonder off connection, play with wonder rewards ect.
Once you get past a certain treshold you are locked out of recieving KP, since there is some leeway in the system some push to a certain degree is "tolerated", at the same time there is the "shame effect" of the warning. unless people know you are a wonder searcher they will call you out for pushing as there is a big fat red mark on all your wonders saying this person pushes!
Fun part of the system is that wonder searches are able to get you into negative numbers. I probebely never ever will get out of the warning ever again since each wonder I have gotten where I got more than I invested gets my allowed KP limit down and down and down. past 2 months I havent searched any wonder and spend hundreds of KP at others and I am still miles away from being able to recieve KP again.