Apparently animals will run away and sprinkler heads can be marked with perimeter wire so that the gadget avoids them.
This actually seems solvable by robotics, but it's not a viable solution for beacons or markers as they are meant to be "passed over" by lawn mowers.
http://techcrunch.com/2015/04/13/irobot-is-working-on-a-robo...
"iRobot: “Use of the iRobotRLM [robot lawn mower] will increase lawn mower safety. An estimated 1,517 lethal accidents occurred with lawn mowers through the years 1997 to 2010. It is reasonable to assume that many of these injuries and deaths would not occur if consumers used a robotic mower. More than 17 million gallons of fuel, mostly gasoline, are spilled each year while refueling lawn equipment. Abattery poweredRLM will reduce emissions, gasoline spills, fires and other such accidents.”NRAO: “iRobot cited multiple statistics of grim accidents and spilt gasoline to assert the public benefit of approving its wireless robotic lawn mowers. However, there is already a competitive market for robotic lawn mowers using wire loops [buried edge wire], which has somehow failed to stanch the stream of ghastly accidents and spilt gasoline that iRobot associates with the mundane practice of lawn-mowing.”"
"An estimated 1,517 lethal accidents occurred with lawn mowers through the years 1997 to 2010."
No data on the "1,517 lethal accidents" to prove that they were caused by fires or anything that a robotic vacuum solves (although I'd be happy to be sent a link proving this). So it's not "reasonable" to assume that these injuries will be reduced - the icing on the cake is the last sentence which essentially contradicts the first...
"there is already a competitive market for robotic lawn mowers using wire loops [buried edge wire], which has somehow failed to stanch the stream of ghastly accidents and spilt gasoline that iRobot associates with the mundane practice of lawn-mowing"
Edit: Just realized the fist statement (claiming safety) is by iRoomba, the second statement (disputing this) is by the NRAO.
So iRoomba (the one selling the product) claims it will reduce vacuums. The NRAO pointed out that despite a "competitive market" for robotic lawn mowers injuries have not been reduced.
Edit 2: Data! http://www.ncbi.nlm.nih.gov/pubmed/16361919
It's one thing if your vacuum sucks up a kid's toy, or harasses your cat. Imagine the potential liability if your robotic lawn mower left your yard and entered your neighbors.