I’ve worked in private golf clubs as a waitress. If a bottle that was merely tasted was sent back, and it was still good, it might* be served by the glass if it was a bottle from the house wine list (which had by-the-glass servings anyways). If it was a non-house wine (something ordered off the list, like a vintage) and the wine was still good but the customer was being a jerk, we charged the customer and poured the wine down the sink. It’s a shame, but it can’t be recorked and it can’t be offered as a house wine, and it can’t be suggested to another customer since its opened - that means that there is no guarantee that whats in the bottle is whats on the label.
We also dumped all the leftover wine from bottles (some tables order a couple of bottles throughout the night, and might leave 3/4 or 1/2 or something in the last one), although there was plenty of staff willing to dispose of it themselves
The only times a bottle was opened away from the customer was when a house wine was ordered (not enough staff/time to cover the demand) or if we were really just too busy to take the time to do so at each and every table (trying to serve wine to 300 people all at once - on an a la carte evening).
You’d be amazed at how much good food and drink goes into the garbage or down the sink in a busy restaurant/dining room. And you aren’t allowed to let staff leave with any of it.