Built elements which are required to ensure that a site is structurally sound are sometimes not foreseen when a site is designed and are not known about until the site is constructed.
For example, support struts can be required to ensure antennas are stable but may not be known until a site is in the construction phase. Engineering requirements of existing buildings and structures can also require a minor change in the site design once it is in the construction phase.
Like any developer, Proponents outsource many elements of the site acquisition process including the construction of sites. Sites can be built 18 months to three years after the original site design has been signed off and adding additional elements such as support struts which are necessary for the structural integrity of the facility are not necessarily checked off with the original site acquisition team, nor governed by the same parameters or operating procedures such as ensuring visual effect is minimized.