I assume this is an upscale restaurant and yes, it would be highly unusual to a) force the patron to use the restaurant's cleaners, b) force the waitress to pick up the cleaning, and c) force her to pay. I could imagine such behavior from a sleazy diner somewhere run by a total @hole, but not from one of our better establishments.

Doesn't sound like there was any guilt trip laid on by the waitress; the OP had to cajole that factoid out of her. So I assume she is blameless and a victim here. Well, not entirely blameless; she did spill the drinks, but accidents do happen and it doesn't sound like she spilled them intentionally :-)

I understand the OP's reluctance to post the name of the resto for fear of retaliation; a manager that tacky could fire her.

I like the suggestion of popping in and leaving her a nice tip; alternately, send her flowers or chocolates which could brighten her day working in such a sweatshop.

And three jeers to the restaurant for not comping anything. At the very least, a round of (intact) after-dinner drinks, free dessert, or something along those lines.

I like "Drinks are on me" ... my standard rejoinder (yes, it's happened more than once in a resto, and several times on a plane) is to take my index finger, dip it into the spilled liquid, taste it and proclaim "I ordered the gin and tonic, not the vodka tonic!" (of course depending on what's spilled, "I ordered the 1982, not the 1996" or "Sorry, that was a Lagavullin, not a Glenlivet" ... etc.) And it goes without saying, one should not make a scene, laugh it off, and get back to enjoying the food.