I'll also mention 2 of the most important things when it comes to a live broadcast event.
NO DEAD AIR. NONE. ZERO. EVER. EVER. It jacks with the Nielsen ratings system and is also just a bad look for your network. Something needs to be going out over the broadcast. There are multiple redundancies in place to deal with these situations. Every live event has multiple dedicated PLN circuits riding separate carriers (AT&T, Level3, etc) to Master Control. Additionally, you'll have a sat truck on site bouncing the live feed off a satellite to an antenna at Master Control should all of the redundant fiber optic carriers decide to take a dump all at once. Yes, that happens believe it or not.
In addition to communications redundancies, you have alternate content feeds queued up so if you lose your main broadcast, something is being broadcast. These alt feeds trickle down to bump music and things like the sponsor spot in question. If you see dead air, you automatically know multiple systems have experienced a catastrophic failure and there are easily 100 people both on site and at Master Control running around like their hair is on fire.
AD REVENUE PAYS THE BILLS. You don't jack with the commercials. Ever. The commercials must run. Every time a commercial airs, an "as-run" script runs to make a log of it and that kicks off a query to a QA server that analyzes the performance of the commercial that aired. It checks for any glitches, gaps, etc. and ensures the commercial metadata (length, bitrate, etc.) matches what went out over the air. That report is then sent to the ad agency that paid for that spot and if there were any issues with the spot (commercial), the broadcaster doesn't get paid. If one of your Master Control operators comes back from commercial a second too early, the company loses that ad revenue and the operator gets a ding. Too many dings and you get canned. To prevent things like this happening, every Master Control operator has a live audio feed to the production truck on site. Those feeds are also redundant with both fiber optic circuits and POTS (plain old telephone service) lines. When they get ready to come back or go to commercial, both the truck and Master Control do a 10 count and count back to each other to ensure the feed is switched from Master Control back to the live venue at exactly the correct moment. It's crazy what goes on behind the scenes of something so common as a sporting event.
I'll also mention 2 of the most important things when it comes to a live broadcast event.
In addition to communications redundancies, you have alternate content feeds queued up so if you lose your main broadcast, something is being broadcast. These alt feeds trickle down to bump music and things like the sponsor spot in question. If you see dead air, you automatically know multiple systems have experienced a catastrophic failure and there are easily 100 people both on site and at Master Control running around like their hair is on fire.