Stadiums & arenas
Tiered inventory, fast entry, one revenue picture
Price the ground in tiers — general, premium, VIP — each with its own capacity, and let issuance enforce it: a tier cannot be oversold even under a simultaneous rush. Define doors within the ground that admit only the tiers you assign to them, each with its own limit and its own re-entry rule, and sell hospitality tables as inventory alongside the tickets. Sellout upgrades are opt-in per event: a buyer whose tier sells out mid-checkout moves to the next tier up at the price they chose, and an already-issued ticket upgrades too — general admission straight from the ticket, seated by choosing a dearer seat, paying only the difference. Moving down stays a refund, deliberately.