The young garda on the checkpoint in Muff, Co Donegal, looked exhausted. Drafted in from Kilkenny, he still had an hour to go before finishing his 6 a.m. to 2 p.m. shift, and the wind-chill factor was telling.
A line of Northern Ireland-registered cars stretched towards Moville and Greencastle.
The scenic R238 route hugging the eastern shoreline of the peninsula is very popular with day-trippers from the North. In winter hundreds of Northerners use the opportunity to visit the narrow village of Muff, not just for sightseeing, but to fill up with "cheap" southern petrol, and to eat out.
In the evening and at night there is another surge of traffic and business, as young (and not so young) Northerners drive to socialise in the discos and music bars of Inishowen towns.
For the young garda at Muff, the routine was physical and repetitive throughout his eight-hour checkpoint stint.
Hand out, to halt the car; lean to the window and ask: "Have you any meat or milk products? Have you been near any ports or airports? Can I inspect the boot?"
Then round the back, to open the boot for a quick glance; slam it shut and wave the driver on over the disinfectant-soaked mats. The same routine, repeated perhaps a hundred times every hour.
At 1 p.m. on Sunday the afternoon excursions had not yet built to a peak, and the delay was just about tolerable. The word from Bridgend, the main crossing point from Derry into Donegal on the routes to Letterkenny and Buncrana, was that queueing time on Saturday had been on average 1 1/2 hours.
Precautions against foot-and-mouth infection in this part of Co Donegal might be described as "good in spots".
Two miles along the R238, Mary Deeney's bar and restaurant had big notices, and sterilising mats, not only at the door of the premises but also across the entrance to the car-park.
However, a number of similar establishments on the same few miles of road had no obvious facilities.
In the main square of Moville, there was a strong and reassuring whiff of disinfectant. It seemed to waft mainly from McNamara's Hotel, which had notices and mats at every door.
In the pretty village of Culdaff, the popular food and music venue, McGrory's, also had mats and notices, as did another pub in the village.
A few miles on, in the scenic village of Malin, a regional award-winner in the Tidy Towns competition each year for the past three years, there was a soaked mat outside the premises of Boggs Family Butchers, even though the shop premises was closed.
Mr Ronald Boggs was annoyed, however, and had made a phone call to the Department.
He had seen three full touring coaches from Scotland pass through; normally a welcome sight, but pointing up some inconsistency in the travel restrictions and advice at this time.
Farther on, in the town of Carndonagh, the Centra supermarket had a novel device, two thick blocks of disinfectant-soaked sponge for shoppers to walk over.
Elsewhere in the town, Mick Herron's antiquarian bookshop, a good spot for a couple of hours' browsing on a winter Sunday, also had a soaked mat outside.
But most bars and smaller shops on this limited tour had no precautions, and it is not at all clear that they could be expected to. Total saturation of country villages with mats and disinfectant could give an impression of endemic plague without significantly affecting the chances of foot-and-mouth infection in the area.
There was little or no livestock to be seen at the weekend in the frozen fields and on the snow-capped mountains of Inishowen.
A few sheep did graze in fields around farmhouses on the main roads, and the word was that some farmers had locked the gates to their land.
But the crunch will come if the crisis lasts. Special measures will have to be taken if the vast annual tourism exodus from the North into Donegal is to be facilitated.
Passing back (without any hold-up whatsoever) into Co Derry through Muff at 5 p.m. on a bitterly cold Sunday evening, the shift had changed and the Kilkenny garda had gone for a well-earned rest.
But the count of cars in the queue heading for the checkpoint and into Co Donegal at that time was 175, only 12 of which were Donegal cars, the rest all being Northern Irish or English registrations. Clearly, something has to give.
To make matters worse, a notice inside a Carndonagh supermarket raised the possibility that some obvious channels of possible virus transmission are being totally overlooked.
It read: "Fresh shamrock for posting available here from Friday, March 2nd."