The problem for all companies and especially smaller businesses is they do not vet their employees to a level commensurate with the level of trust and access to be placed on them.
Personnel security is the last thing businesses think of and never dig deep enough to determine if the person is a bad hire or potential "Trusted Insider". Government have a classification system in place and classify resources appropriately and vet people who have a need to know need to access. Businesses needs to bite the bullet and do the same, potential employees may not like the idea of a background check and interviews about their personal habits that may make them a risk, however if done correctly and with appropriate protection mechanisms they will accept it if they want the job.