Yes!
The original query was that after the crew had requested to line up - so I guessed that they were stating that they were ready.
However - yes - if I give a line up clearance without checking if the crew are ready for departure, then that is my issue and the subsequent go around would be too!
Personally I won't give a line up clearance unless the crew have reported ready for departure.
edited to add - having re read the original post, I wouldn't assume any one is ready for departure, I always check. Mainly as I have been caught out before now in my youf!
louby