recently we had a small discussion about deprecating some of the operators for boolean arrays. This discussion seemed to have ended by large in the consense that while most boolean operators are well defined and should be kept, the `-` one is not very well defined on boolean arrays and has the problem of the inconsistency:
- np.array(False) == True False - np.array(False) == False # leading to: False - (-np.arry(False)) != False + np.array(False)
So that it is preferable to use one of the binary operators for this operation.
For now this would only be a deprecation, but both operators are probably used out there. So if you have any serious doubt about starting this deprecation please note it here.
The Pull request to implement such a deprecation is: https://github.com/numpy/numpy/pull/4105