Dani - Who cares what the tower says!
As a professional aviator, it is YOUR decision to make a judgement if a ship affects take off performance. Can you do that visually? NO.
It doesn't matter if ATC say the ship is actually off the end of the other runway... he doesn't have your company performance data, and he doesn't know if the aircraft is in your E/O splay.
Old aviatiors have made it to be old aviators because they've learned how to protect themselves and their aircraft. The number of times in my relatively short airline career I've been set up by ATC/Groundstaff is staggering. The key to being a fine aviator is to take advice from others, but make the decision for yourself.
Take offs are optional. If you aren't entirely sure, then you don't go. Who cares if later its proven that you were wrong and the ship was out of the way? You have not taken any unnecessary risk, and THAT is the mark of a fine aviator.
As mutt would know, most people are very surprised by just how large the E/O area actually is, and how small an obstacle can still cause havoc!