Get off the Cricket thing. The phrases regarding lines are older than Cricket, and the practice of demarcating things with lines real or imaginary is ancient.

In fact, the various sayings are not idiomatic. The meaning is easily understood by the phrase and would arise in the normal course of conversation, and can be tarnslated directly into any language without ambiguity of meaning.

Mark or line means a boundary mark on a piece of land. Thus, the negative connotation of the phrase.

One day, Bob took a staff, drew a line on the ground, and told Jenna: “You can do anything you want, but f you cross this line, you will become the biggest monster that ever lived”.

Soon enough, crossing the line became a phrase meaning going really far. The ones that crossed the line lost every trace of humanity. The crossers never come back, they never return in their old form and never regain their old grace and dignity.
Crossing lines comes in different forms, but the concequences are the same.
Just for example: you can rape, burn villages, steal, destroy monuments of cultural and historical importance, or kill and hack off limbs but if you say “Attack on Titan is a great anime” you’ve crossed the line.

Crossing lines is serious businnes bruh, even more serious than religion, politics, sub vs dub and having spelling mistakes together. Never cross the line.

In Hindu mythology Ramayana is well known around the world. King Rama is in the jungle for 14 yrs to fulfill promise given by his father with his wife Sita and brother Laxmana. During this period they killed lot of bad creatures called Asuras whose king was Ravana. For this and to take revenge of his sister’s insult by Laxmana he tricks Rama in following a deer made of gold which another Asuras. Laxmana is with Sita for her protection but was forced to go to check on Rama as Asuras does one more trick by calling him for help in Rama’s voice. While leaving Laxmana draws a line around the hut and asked sita not to cross it until they return. Asur king Ravana then enters in the form of sage who makes sita to cross the line on the pretext of giving him food and abducts her since she crossed the line. Based on this story similar idioms exist. Crossing the line means behaving in such a way which is beyond acceptable limits laid down by society.

Is this like being one toke over the line????

^^^^Sweet Jesus…

I think of a mark as a line, or more specifically a place, that you must stay at, within, or behind, or you get penalized. Line doesn’t really quite define mark accurately to me, a mark is more specific. The mark is an expectation of where you “should” be at a given time. It can be used for behavior or a thought process as well.

On your mark, get set, go.