They do have some agreements with OAL's but they're never of a generous nature for the most part. I know at AN we had ID75 with them, so it was never really worth all the hassle.
I have a good friend who works for them - their travel benefits are certainly not of the usual standards, but they do exist.
Then again, we are talking about the airline that can go to Everett (Chicago these days I guess) or Toulouse and pay cash for a mega plane order. There's a definite correlation in my mind between the way that SQ views and has strict policies on both say nonrev and Frequent Flyer & it's bank balances and let's just say UA as an example. Both are poles apart in their views/policies on the above products - but so are the respective finances of each carrier. SQ's focus is always on a superior experience for any customer as well as it's bottom line.