If I can remote control a cheap wifi robot using it's camera and my phone I should be able to do the same with a $2500 robot.  Lag is minimal or non existent if you have decent wifi.  If it's a safety thing for the mower, just don't let the blades be activated.

We have strong wifi coverage over our entire acreage and would love to avoid going out and messing with the bot or dealing with patrol point hacks to get the bot to a specific spot, check something remotely etc.