Unless you are a very skilled player and you plan on taking the pot with skill and without showdown, just muck the worthless hands like 27o in a full ring game in all situations. I don't see the point in playing it even after the whole table limps. What kind of flop are you expecting to see? Maybe a hand like 45o or something that has potential, but hands like T4o, J2o, 38o, etc. need not be played from any position, even if you are getting 20:1 odds from the SB.