I thought they only deducted if the athlete stepped both feet beyond the red. I can't find the info though so I'm not sure.
From:
http://usasf.net.ismmedia.com/ISM2//Worlds/2014/docs/USASF_14_Worlds_CH_Rules-Regulations.pdf
II. COMPETITION AREA
A. Participants must start and end in the competition area and
may line up anywhere inside the competition area. The
competition area will be determined by the tournament
director according to the size of the facility being used.
B. Approximate floor size will be 54 feet wide by 42 feet deep
(9 strips).
C. All skills must originate and be completed within the
competition boundary. No lineups, skills, or transitions are
allowed outside of the competition boundary.
The
competition boundary is defined as the actual competition
floor/spring floor, the carpet bonded foam panels that
connect to the spring floor, and any additional border that
supports/surrounds the floor.
D. A 3.0 deduction will be assessed per occurrence for an
athlete that makes contact outside the competition boundary.
Stepping on, or just past the boundary tape is not a boundary
violation.
So the competition boundary includes the red border. Deductions (notably
3.0 points) are to be taken if athletes make contact outside the boundary (off of the red).