do auction houses allow consignors to bid on their items?

noob question...i'm probably stupid and burning money for not knowing the answer till now...but how many houses allow this practice? i know you can obviously tell your friend to bid up lots for you but can you just diy?

for some auction houses i probably would prefer the house owning the lots versus consignments.

I believe that the consensus among most baseball card collectors is that they object to owners bidding on their own lots. And that auction houses typically try to support this preference.

I note that other areas of collectibles do not always object to owners bidding on their items, so long as they are responsible for the same fees and other costs as any other potential winner.