lines that bind

There are lines you don't cross everywhere.

 Don't yell fire in a theater applies to writer's 

in too many ways to describe. 

There are lines you don't cross.

When in Rome sometimes means wearing a Burka these days.

Lines you do not cross... 

Never hit someone over words is one I live by.  Freedom of speech

 Lines.... everywhere. 

Do Not Cross = No Cross.