Your competition is only going to go so far. "I got turned around in the datacenter, oopsie" is something that happens. It's not likely that Amazon is going to send someone over a fence, regardless of how low it is. That's crossing the line.
Amazon may not be sending someone in. But there could be some "paparazzi" out there who would like to get a photo of this for his/her fame. Then, it will be visible to amazon, facebook et al.
But its ignoring standard practice at even low security places for example the fences at BT Labs (Uk's Bell Labs) where about 50% higher and curved inwards (to keep intruders inside.
Though one visiting US telco guy said of BT Labs "Fuck Me it's a Prison"
vaguely related: http://old.post-gazette.com/pg/06188/704045-28.stm