There are no guarantees. I have heard of people resorting to balanced cables for much shorter lengths because their situations involve lots of EMI. (Do you live near a radio/TV transmitter?) Recording/mastering studios have miles of cables all influencing each other.
So, my cables are no less antennas than anyone else's but, as far as I can tell, they are not picking up any signals inside my apartment. Literally, YMMV.
Kal