There is no monetary cost associated with a rescue of a guy in a river. All the equipment and manpower is at hand and in use regardless. All the accountants in Dante's third circle of bureaucratic hell could not distinguish a fiscal period with the rescue compared to without.
The only stupid thing was admitting that he'd swum across, for which there is no proof, meaning no evidence, so he should just say he fell in and never cross the border, or better yet, say nothing and kick his friends in the ass. If he had gotten into trouble in the water, the only purpose for calling for help at night would be to recover his body a little more quickly.
Wotta buncha pussies.
If I ever get drunk (or not) and decide to jump into a dangerous river (has happened for good and bad motives), I hope my friends would either physically stop me or have a drink in my honor. Calling the authorities is such a lame ass move. Would immediately disown anyone like that.