Yes but the issue is not whether or not the "paste" will be sent anywhere, but how many lines there are in the buffer.
The following examples prove the above.
/clipboard A
//echo -> $cb(0)
- Returns 1 line.
/clipboard $+(A,$crlf)
//echo -> $cb(0)
- Returns 1 line.
/clipboard $+(A,$crlf,B)
//echo -> $cb(0)
- Returns 2 lines.
/clipboard $+(A,$crlf,B,$crlf)
//echo -> $cb(0)
- Returns 2 lines.
So in short, regardless of how many crlf's there are, there will always be one more line.. and mIRC check looks at how many lines are in the buffer, and isnt concerned whether those lines will be pasted into IRC or not.
Eamonn.