If they were going to fight for the corporal, I would agree in principle, as getting your own back SHOULD be the highest priority. THAT tactic/response, also sends the message that holding your people only gets the holder's shit fucked up, as American service personnel might put it. This trade only sends the message that there is profit to be made by grabbing at prisoners. Even those who might look askance at losing a few men on another sort of raid might be willing to make the trade of 10 fighters killed kidnapping a soldier, if they are going to get 20 or 200 of their own back.

Call it what you want, this is simply another example of paying Danegeld. Those idiots who say they would refuse to serve in an army that won't pay to get them back have the vaguest hint of a point - namely that a military & government SHOULD make every effort to get them back, even if getting one man home safe gets 10 men killed. However, they are being penny-wise and pound-foolish, for a government that will make this trade is only putting a target on the backs of all their other soldiers, including the future soldiers who are demanding the trade. If they will trade a couple hundred guys for a corporal, then even a private must be seen as a worthwhile target to the enemy, let alone a sergeant or commissioned officer!

"It is wrong to place temptation in the path of any nation
For fear that they should succumb and go astray,
So when you are requested to pay up or be molested,
You will find it better policy to say,
'We never pay anyone Danegeld,
No matter how trifling the cost,
For the end of the game is oppression and shame,
And the nation that plays it is lost!'" - Rudyard Kipling "Danegeld"