Help out the Clueless White Girl (updated)

I suppose I deserve this for what I did to Happy Feminist. Recently she wrote an extremely reasonable post detailing the new rules for discourse in her comments sections. Ever the wiseass, I respond in the comments with "So, to clarify, can we or can we not use ethnic slurs?"

Today, just a few days, later, ethnic slurs are very much on my mind.

In a discussion on illegal immigration someplace else, I wrote:

That said, I am a particular fan of boat people. Anyone with the brains, guts and fortitude to build a raft out of old tires and sail it here has genes America needs, IMHO.

Not wanting to offend, I had even looked the term Boat People up in Wikipedia to make sure central Americans didn't consider if offensive.

Having used it, I was swiftly told that I had slurred Asians. I think it is pretty clear from the context that I did not intend it to mean Asians, both because of the surrounding conversation of central Americans and because anyone who built a boat out of tires and sailed it here from Asia would have to be very impressive indeed to survive the trip at all. As is also clear from the context, I didn't mean it as a slur, either. As someone born in 1978, I've mostly seen the term used for central Americans, Haitians in particular. Whatever use the term had in regards to people escaping from communist Asian countries was quite literally before my time. (Ever notice how everybody is always trying to escape from communist countries? The only one who thinks they are great places to live is Michael Moore.)

I could make the argument that I also am a boat person, though my family's boats were a few hundred years ago and bigger.*

I've learned my lesson about the term "boat people."

But I guess what I need to know now is:

1. How do I know if something is an ethnic slur?
(e.g. The Shorter OED doesn't have the term "boat people." The Big Dog says that boat people is a term for people who have fled a country by boat but doesn't mention any slur aspect whatsoever. (If onelooks up another common ethnic slur, "Disparaging and Offensive" are the first two words of the definition.)
The wikipedia article also treated the term neutrally. Googling the term reveals seemingly neutral uses on CNN and an organization called Boat People SOS raising money for immigrants displaced by Hurricaine Katrina.
I realize what is and isn't a slur is a matter of opinion, but is there a way to find out the general consensus?

2. Where do I find inoffensive terms?
Repeated requests at the other conversation for a non-offensive term for people who are not here in this country legally have thus far been ignored. At wikipedia, people say the term should be "undocumented aliens" but that sounds offensive, too. I hear "undocumented workers," too, but that term seems weird given that the person who is here illegally whom I know best doesn't work.
At this point, I don't even know where to go for the information.

Any suggestions?

CC

Update: Just so those of you who really do associate the term with Asians don't think I'm nuts, here's some pretty decent sources using it in a non-Asian, non-ethnic slur sort of way:

CNN

NPR

The BBC

Amnesty International

and someone was kind enough to email me and tell me that Thomas Friedman uses it in "the Lexus and the Olive Tree" where he makes the same point I did about the genetic possibilities of Central American immigrants who get here through acts of great courage.

*Sometimes I stop and let the idea that we are a nation founded by people who had the courage to get on those boats quietly blow my mind. Is there any question why we were the first people on the moon? America has done some rotten things, starting with the Native Americans, but it's hard not to be proud to be an American as I think about the people leaving home and striking out for the New World.