Looking at the screen shot, I suspect it’s a deliberate means of taking points away from their weakest players to force attackers on to their stronger defences.
This is a strategy that was revealed in the thread @Duaneski shared - where an alliance has a large variance between their bottom and their top players, they ask the bottom players to field 1 man defence (near the edge just to make them a tad more annoying to kill). It’s a valid strategy, because now instead of the weakest teams (which would be a sure 1-visit win for the opponents anyway) costing you 30 or 40 points, it will now only cost 5 or 10. It also ‘suckers in’ opponents who are not aware that they should leave the 1 man defence alone and then waste a flag taking it out.
While it’s a valid strategy under current rules, I’m sure there’ll be an argument about whether it is ‘fair’.
It becomes a losing / stupid strategy if too many field 1 man, but it doesn’t look to be the case here.