I used to fly into Tunis regularly on business with a BA franchise (can't remember what it was called) out of LGW. I was working in Sfax at BG's facility. The flight used to have 3 or 4 rows of Club, which usually had 5 or 6 people in. The rest of the flight used to be full of silver hair off for some cheap winter sun.

Often time the oil companies will subsidise specific routes or at least give a guarantee of traffic.