The league schedule generator lets a coordinator pin a match to a chosen night ("Hawks v Owls -> 2026-11-03"), earlier or later than where it fell. Every other editing pass already had a random-league check; pins did not.
eval/fuzz-pinned.mjs builds random leagues, pins one to four random pairs (half onto an existing league night, half onto any date from three days before the season to a week after), then checks that the schedule is still valid, no match was lost or invented, each reported pin sits on its date at its reported court and time, and a refused line changes nothing.
Result. Seeds 5 to 8, 300 leagues each: about 3,000 pin lines, 935 pinned, 1,917 refused with a reason, 0 faults.
The first run reported 236 faults, all mine. The checker compared match fields that the move records do not carry (home index versus homeName), and counted the pinned flag as a change on a refused line. Fixing the checker took the count to zero. A fuzzer needs the same scrutiny as the code it tests.
Limits: synthetic leagues only. No real league's pin requests were used. The check is pinned in the test suite at 60 leagues.