Self-serving, but: the backroom of the Stadium is inaccessible to anyone but the owner, and inside are some black guild card players! Any chance for just some adventurers in there, and making the entry token a 500gp 'Pass Coin' you buy from Marvin Pond (proceeds hopefully going to the Councilor maybe?)? It could definitely be a cool meeting spot for secret dealings, games of chance or otherwise.
If you're poking around there too, the office is just a little hammock and some key cupboard. Any chance for renovation? I could pay... lacking storage is not great for me.
This could function like the House of Trade storage keys, in which the Councilor who rents the Stadium can distribute backstage passes.
If anything, it may be overdue for some of the Stadium's legendary heroes, like GOALSMASH, to be giving out autographs...
You can purchase stadium keys and disperse them to your employees as a Stadium Councilor. If it is a matter of paying... I am sure the council could find someone to rennovate for a sizeable sum.