By Treetools reckoning 'Joe' is correct in his assumption that SRT climbing (Ascent and Work Positioning) IS ALLOWED in the ITCC events.
Non-allowance of the Rope Wrench is product specific. The ITCC restriction does not apply to the climbing method in which the Rope Wrench is employed.
TAC credibility would indeed be stretched if SRT Work Positioning was banned outright in international tree climbing competitions.
Many regulatory bodies consider the term 'Work Positioning' to encompass exactly that - work positioning - regardless if the climber is on one rope or two.
The Rope Wrench just happens to be one of the few SRT Work Positioning tools to have gained almost universal acceptance with aerial arborists. Naturally, everyone assumes industry endorsement should be transposed to the ITCC but this line of thinking is obviously flawed.
The Petzl Rig and Petzl I'D are two products deemed safe (by the ITCC) for working on a single line in a tree.
Both products were allowed use in the recent ETTC - if we are to believe the comment below.
There are, of course, serious reservations regarding the safety of the Rig and I'D in tree work and neither product is universally accepted by working aerial arborists. But that is another matter altogether.
So, to recap… SRT Work Positioning IS endorsed by the ITCC. The use of the Rope Wrench IS NOT (at least in 2012).