I probably wouldn't give it a second thought if I needed fuel and a tanker was filling the station's tanks. I suppose it's the cautious thing to do, but then if I was worried about stirred up contaminants I should ask them when the last time their tanks were filled. How long does it take the fuel to settle. However, I now refuse to buy gas from a station with a reader board showing a cash price, because around here their unposted credit card price is 10-15 cents/gallon higher.