On French radio a spokeperson from the Sat company operating the satellite in question said that what they saw was a cluster of debris, but that included " a wooden pallet and some tighting ropes of different colors "...
If this is true , the international show will have to go on a little longer...
As to debating if a transponder go stand by automatically when changing squawks,
what is the relevance ? It will not tell you if the aircraft is there , or in the North arc , or in the forest of an isolated island somewhere .