To truly prove that some things are just a matter of time, I came home on Friday after work and found:
Yes, the BKP vommed on our new(ish) Corona. Luckily, using the "water only" technique described in the booklet that came with the sofa, I got all of the offending matter up and off. Three hours and much fretting later, the spot had returned to its original, appealing avocado hue.
Funny how much less protective one feels about a "big ticket" purchase after knowing that another living thing regurgitated on it.