No you don't have to remove that text, in almost all AssaultCube configuration files (.cfg) anything after the double backslashes "//" on a line is ignored:
...you'll only see "Hi there..." once because the second one is commented out (i.e. has "//" before it)
[SELECT ALL] Code:
echo Hi there...
// echo Hi there...
// This is another comment that'll be ignored by cubescript
...you'll only see "Hi there..." once because the second one is commented out (i.e. has "//" before it)