A tailgater is a value taker. While it is fine to see a demonstration by a more experienced PUA in a seminar or bootcamp setting, hovering and hoping to benefit from other’s sets when the tailgater is not friends with the PUA is generally low status behavior.
In the worst case, tailgaters will interrupt sets, DLV the PUA through uncalibrated behavior, and generally act as a cockblock. The best way to deal with a tailgater is to politely tell him to go away, tell him to RTFM, distract him with a pawn, or simply ignore him.
Source: Vincent Chase