Plywood is a lot cheaper (and easy to remove) than hiring a security guard to protect your business from idle vandalism. Why _wouldn't_ the businesses be board

Plywood is a lot cheaper (and easy to remove) than hiring a security guard to protect your business from idle vandalism. Why _wouldn't_ the businesses be boarded if they're unattended for a few months? (Note that boarding up businesses predated riots by months, in my experience).