It can make a big visible bump in a volatility surface, but experienced option traders are trained not to react like robots, but think instead of following blindly (otherwise it would be very easy to fool them, since it's a relatively illiquid market in which anyone can have a lot of leverage).

In that sense it's similar to poker; you don't have all the information to analyze what other players do. In this particular case, is it an informed trader or a noise trader?