Although digital advertising campaigns can become valuable business assets, it is difficult to steal or copy them successfully, even if access could be gained which is unlikely. The higher risk would be from an in-house person, or agency with access to the account.
PPC security is an often neglected aspect of account management which can lead to major losses. A successful PPC campaign should be treated as the valuable business asset, which it what it is. Articles on this describe how to insure good PPC account security.