In chapter 6.5.2 following is described:
ControlGroup that references the same Variable or Method (in ListToBlock or ListToRestrict), even if both ControlGroups are being accessed by the same Client. One or more entities may call EstablishControl on separate ControlGroups that do not share any Variables or Methods (in ListToRestrict or ListToBlock).

Question is: Should it be allowed for one and the same Client to acquire a lock on two ControlGroups with overlapping Variables or Methods at the same time?

PH comment: I would enter a mantis issue on this – I think you are right that text should be updated – if a single connection grabs two locks, they could have overlapping variable and it would be fine – we should fix this text to state it better.