At my kids' school, if they do things like this, this is what they do. Because yes, Teachers are tapped out and very busy. And it can be a real chore, for them. Teachers are very busy.
So at my kids' school, they have a staff person that is a liaison with the community. This person, gets community businesses, to "donate" services or products, toward the school's fundraising drive. And, my kids' school, gets MANY MANY, "sponsors" this way. Any funds garnered by this "auction" goes ALL to the school. And the school of course, displays the school's sponsors/donators toward their auction. They have banners and they are invited to the auction, given leis to honor them, and they are listed on any program fliers etc. And the "prizes" that they have on auction... are good things. Not knick-knacks or dust collectors. But services or goods, by the community businesses. And it is also a write off, for them. So it is win win.
*ETA: and the community businesses like contributing, because: they get more clients or business this way, and publicity for the business. And, many of the community businesses, also have their own kids that goes to the school or nephews/nieces or they are "alumni" as well. So they happily contribute.
And my kids' school, makes a LOT of money, this way.
Some "prizes" for auction, are even weekend trips, or stays at a local hotel, for example.
There are many ways, to do school auctions. Other than, using the teachers to contribute most of it.
At my kids' school, the auction or fundraiser, is used to benefit the school AND the Teachers... per supplies/technology/library/art or PE supplies etc. and materials.
Again, there are many ways, to do school auctions. Which also then may lessen the school's manpower in having to staff it and prepare for it off-hours...and make things for it and takes up time, non-school time, for the Teachers. And the Teachers, ALSO can actually enjoy the event, and actually have fun and even bid for the things in the auction too. Since "they" are not the auction.