Interesting thought about the problem of privacy and location awareness:
" Soon, I'll be able to rely on a mashup between Google Maps and my personal blacklist to avoid running into undesirables in restaurants. It's even possible the airlines will let me specify the types of people I'd prefer not to sit near."
I don't really think, that's going to happen, because I can't imagine people to let other people access their specific position. That would be too much of an intrusion into people's privacy.
A feasible scenario would be to provide certain people with inaccurate position, for example in which town, or in which neighbourhood you are at the moment, to arrange spontaneous meetings with friends who are nearby.
Also a statistical analysis of data is a possibility:
"And I'm sure that solitude optimization algorithms will soon help me avoid traffic on the roads, crowds at the mall, and other types of UFO swarms."