Most home owners who spend a fortune keeping their front lawns beautiful are resigned to see their lawns becoming the toilets of neighborhood dogs. There are simply no easy way to enforce their property right against canine droppings.

Although fencing is no solution here, it has been an effective way to enforce property right of large real estate such as cattle ranches against neighbor's overt encroachment.

In Amsterdam, the Netherlands, professional anti-squatters are used to protect unoccupied apartments and buildings against squatters. Instead of being paid to do the job, anti-squatters have to pay a monthly fee to an anti-squatting agency to be assigned unoccupied quarters.

This unusual arrangement arose out of acute housing shortage due to rent control. Five out of six homes in the city are rent-controlled, most of them owned by semi-public housing associations (Financial Times). Rent of un-controlled apartments can cost more than 6 times the monthly fee to become an anti-squatter. So anti-squatting is a way to have a cheap though occasionally very temporary roof over anti-squatters' heads (WSJ).

Nervous property owners are happy to register unoccupied buildings with the referral agencies since the service is free to them. Rather than going through the hassle of evicting squatters later on, the owners simply bring in the anti-squatters as soon as the buildings become vacant; even though they have to pay for the utility.

The squatting culture in the Netherlands grew out of a custom that permitted legal squatting of buildings that have been left unoccupied for at least one year. In the 70s and 80s, it won public backing for exposing property speculation and governmental indifference to residents' housing needs. In its heyday, there were more than 20,000 squatters in Amsterdam and the squatting movement has an elaborate network bordering on a business empire: it publishes a guide to squats city-wide, has its own TV program, Internet cafe, fitness center and even runs coach and bike hire services (The Independent).

But as the number of foreigners attracted in part by the prospect of rent-free squatting increased, anti-immigrant sentiment has led to decline of sympathy for squatting (The Gazette).