Full-rollers can flare, even true full-rollers. Flare is dependent on pin position and core orientation. One of the canonical full-roller drillings is pin-in-palm with a 0" pin, basically like a plastic ball. If you track between the fingers and thumb, that pretty much puts your pin in the track, which is a zero-flare layout. In the glory days of the full-roller, you didn't have cores to orient, so putting the pin in the palm was just fine.
Nowadays, you're pretty much guaranteed to get flare from the ball if you don't put the pin in the track. It's not a release issue, it's a core dynamics one.
SH