Fence, it's always fence.

There is no question, fence is the first step in property security.  Any fence will create a physical as well as psychological barrier, plus mitigate leagal liabilities as well as define criminal trespass.

 When dealing with vacant or undeveloped property, the best value is often temporary or rental fence.  Most commonly associated with active construction sites, or special events, temporary fence is becoming the Property Manager's salvation. 

 Dark nights, long week ends, unattended locations are interpreted as "welcome" signs to squatters, vagrants, vandals, teens and curiosity seekers.  Case after case has created legal confirmation that construction sites, vacant buildings and open land is an "attractive nuisance" pratcally inviting stragglers to venture in and wander around, or worse. 

Ultimately, the damage they do to the property, buildings, equiptment or themselves becomes the financial responsibity of some combination of owner, contractor or care taker.  Not to mention the risk they add to the sale of any property.

There have been million dollar lawsuits that could have been avoided, eliminated or dismissed if only the property had been secured by a temporary.

It is not uncomon for me to see half built houses, open trenches, $100,000 pieces of equiptment sitting open for days and weeks on end, inviting disaster, when one phone call could have at least gotten a price to have a temp fence installed.

Not making that call, is inexcusable.  Not securing the site is a combination of risk assessment criteria versus cost.  The worst thing you can do, is fail to advise people of the option.