Most sponsorship agreements are brutally one-sided. The payment is non-refundable, the organizer keeps the discretion to "modify or re-assign recognition at any time," and you often can't even proof your placements before they ship. So when the event is over and you're asked, internally, whether you got what you paid for — the honest answer is usually "I think so." Here's how to make that answer "yes, here's the proof."
The standard wrap-up — a deck with a few booth photos, sent as one big email — is a marketing artifact, not evidence. It's one-way, it's not timestamped, you can't query it, and it conveniently omits whatever didn't happen. If a logo was wrong or a push notification never fired, the recap won't tell you.
Start from the term sheet, not the recap. Write down every deliverable as a discrete line with a clear proof method — what "done" looks like for each one. This is the single highest-leverage step: once the deliverables are a checklist, "did we get it?" becomes answerable.
You don't have the screenshots; the organizer does. The trick is to give them one structured place to drop everything, instead of a thread where proof gets buried. A no-login link per contact, organized by deliverable, means anyone on their side can upload against any open item — and you get a live view of what's in and what's still outstanding.
The deliverables ledger for event sponsors — your organizer uploads proof against each deliverable, you see what's delivered, chase what's missing, and export a timestamped pack to defend a non-refundable spend.