TimTumIt's not the responsibility of LR to check if everyone on Surstromming's roster is allowed to play. They even warned them as far as I can see while they could've said nothing at all. Surstromming should've checked with the admins, but instead they responded with 'unlucky, he can', 'we can play with him :)' and 'unlucky :))'
If LR had any doubt that he was able to play they should have double checked it. It seems like Surstromming genuinely thought he could play, so if no team bothers to check or bring it up to the admins. If they were aware beforehand as they seem to be, they should not have readied up and instead should have contacted an admin to confirm that.