Why jeopardise the future relationship with your customer by installing inferior CCTV cable with a copper coated core (CCA) instead of a solid core like anti-hum cables. Copper is close behind gold & silver in terms of conductivity and resistance to corrosion but these are both prohibitively expensive in the manufacture of cable.

In summary to get a similar current rating from both copper and aluminium cables, the aluminium one would have to be much bigger in diameter and therefore heavier, less flexible and harder to join. It would also inevitably end up being more costly too.
Source: CDA Pub 122 – 1998