From today's "World Wide Words" (c) Michael Quinion at http://www.worldwidewords.org.
"Drowning, not waving? Several readers denied there was anything wrong with a headline in last week’s Sic! section: “Where someone drowns determines their chance of survival.” They argued that drowning isn’t necessarily fatal because victims can be resuscitated. I was so surprised that I checked the verb in numerous dictionaries. All the definitions include the word die, which reflects the everyday sense of the verb. Drowning may indicate a process but drown is surely final. I wonder if a shift in meaning is developing under the lexicographical radar?"
The issue may be one of conversational implicature (rather than logical entailment) Or not.
I like 'shift of meaning' -- at least it's not 'shift of sense'! (Grice, "Do not multiply senses beyond necessity").