Lots of variables here, at a busy airport it could be a logistical nightmare. Some under taxi some under tow, more traffic and activity on the taxiways/increased incursion threat, Communications with ground/manpower, who provides the service... the airport? Like to see the bill for this one... Seems like someone is out to get a piece of the airlines normal fuel expendatures. I am all for single/dual engine taxi at a congested airport, this is a bit much though.
I can see it now, gear pin sucked up at the RWY hold short line by an aircraft powering onto the RWY for a rolling T/O or for that matter any other crap that could fall off a tug.