Numerous Titans got physically involved on the fourth episode of TNA. This would be with a month and half until the regular season, with active players that were expected to contribute to that season.
Personally, the Titans have every legal right to stop this, but there's about a 1-in-a-million chance of Pacman getting hurt in a fashion that would affect him over one year from now, plus he is rather lacking in the paycheck this year, so I see no harm in him participating.
http://wwe.thq.com/roster A lot of old school versions of the current rosters including DX and Hunter Hearst Helmsley as well as HHH. All DX sans Chyna is pretty cool as well as the McMahons minus Linda.