open same file on two machines

[zakaronius]

Mathcad 15 will let two users open the same file without warning.

Mathcad 2001 would warn you if a file was in use by another user.

How is this even possible?

[MJG]

Using Mathcad 15, I receive a warning when opening a file that's already open.

File "..." is in use.  It will be opened read-only.

[VladimirN]

And why not first to make a copy of the file (save it to your hard drive disk) and then quietly to work with it?