Onx is using the best information they have available to them, it's the information they get and the gps in phones that have some error. It usually is pretty close but being on the wrong side of the property line is still trespassing if it is marked as such. Hunting antelope this year the gps in my phone wouldn't move to my current location no matter how many times i opened and closed the app. my location was miles off of where i actually was. Like i've mentioned i seen nothing wrong with what the hunters did, i would have moved the blind off the field edge a ways and apologized once confronted to give myself some leeway since i couldn't be positive of the property lines and would probably error on the side of caution then kept hunting. That is just me though.