Get there on time or early. In the past, Ima Robot has gone onstage as the first band of a two or three band bill, even if they were listed as the headliners.

examples:
The Metro - London - May, 2003 (went on at 9ish, prior to opening band)

The Troubador - L.A. - June, 2003 (went on before Jet, even though Ima Robot headlined)

Sin-e' - NYC - August, 2003 (going on a 9pm, ahead of two other bands. Headlining.)

If they're opening the show for another band, get there on time. This band is prompt!