If P/B withdraw, then the only French ice dance team will be Carron/Jones. Last season, C/J placed 12th; two teams above them (Chock / Zuerlein and Crone / Poirier) have since split, and their respective replacements (Hubbell / Donohue and Ralph / Hill) are unlikely to finish as high as their predecessors. Zhiganshina / Gazsi placed 11th at 2011 Worlds, ahead of C/J, but C/J did beat Z/G at 2012 Euros. However, Coomes / Buckland finished way behind C/J at 2011 Worlds but beat C/J at 2012 Euros, and the 3rd Russian team Riazanova / Tkachenko, beat C/J at 2012 Euros as well.
So it's not a sure thing at all that C/J could finish top 10 at 2012 Worlds and hold onto the two spots for 2013.
Nothing is a sure thing, but it's pretty clear C/J will finish 10th at a home-turf Worlds if P/B withdraw.