Signal 27 can mean noncontact foul as well.
http://www.blcf.org/Special/footballsignals.pdf
I definitely think there should more Intentional DPI called than has been called in the past. I have a friend that is an officials that say he thinks there should be more invoking of the unfair acts clause for intentional dpi inside the 10 yard line.
PENALTY: Unfair act – the referee enforces any penalty he considers equitable,
including the award of a score – (S27).