Thanks for your naughty answer 
Data for planning calendar without this oss note is used to be transported through transport order, so this issue was not raised before. But now with manual maintenance directly in ECC, no authorization check was evoked in the oss note. For sure, I traced the authority objects and have not found any based on plant.
Besides, I'm not sure it can be added in any of user exits of program (MD26/MD25), because it depends on where I want to perform the check.
Thanks for you help,
Carole