Danegeld is a term dating back to the Middle Ages when foolish people would pay the raiding Vikings to not pilalge them. Well the Vikings always came back asking for even more tribute until those people could pay no more, then the Vikings would pillage the place anyway.
In once common parlance to pay danegeld was to pay off someone. In Mafia terms it is paying for protection, protection from accidents like your waiter getting .38 calibre lead poisoning.
So it should come as no surprise to Angela Merkel's coalition government that their unannounced freeing of a convicted killer terrorist to free a German archeologist held hostage in Iraq would have such consequences as what is going on in Yemen in which five Germans have been kidnapped and the kidnappers want some of their people released from jail.
So now the question becomes, does Merkel's government intervene with Yemen auhorities to get those people released? Or will Germany let their citizens languish in captivity, be sold as slaves, or killed? Or maybe Merkel will have the fortitude to risk KSK in Yemen to rescue their diplomat and his family?