In a match last night Team A was playing pretty aggressive defense against Team B. This went on for several seconds; never pinning/trapping Team B, but being a nuisance. After probably 10 seconds or so Team B began to push back and ended up popping a wheelie and landing on top of Team A (back wheels still on foam tiles) Ref started counting to 5 against Team A saying they were pinning Team B.
Team A was able to get out from under right at the 5 count, but was warned the next time they could be DQ’d. I’ve searched for this answer, but have not found anything.
Trapping - A Robot is considered Trapped if an opposing Robot has restricted it into a small, confined area of the field, approximately the size of one foam field tile or less, and has not provided an avenue for escape. Trapping can be direct (e.g. pinning an opponent to a field wall) or indirect (e.g. preventing a Robot from escaping a corner of the field).
Based on the definition of trapping from the game manual and your description of the event I find it clear to say that trapping occurred, however I think it would be very difficult to impossible to determine which team was trapping and which was being trapped. Was Team A holding team B above the field preventing them from escaping? Was Team B pressing Team A against the field preventing them from escaping? I would think that the Referee would have been making the best call possible because the offensive robot would be more likely to be the one trapping.
Its worth noting that, If indeed a trap ends after less than 5 seconds, and all the conditions of G15 are met, then no rule has been violated and thus no warning or DQ is warranted.
<G15> No Trapping for more than 5 seconds. A Robot may not Trap an opposing Robot for more than five (5) seconds during the Driver Controlled Period. A Trap is officially over once the Trapping Robot has moved away and the Robots are separated by at least two (2) feet (approximately one (1) foam tile). After ending a Trap, a Robot may not Trap the same Robot again for a duration of five (5) seconds; if a Team does Trap the same Robot again, the count will resume from where it left off when the Trapping Robot initially backed off.
If the referee determined that it took more than 5 seconds for the robots to separated by 2 feet, then a warning to the trapping team would be appropriate.