Full Idea
Sometimes an exclusive 'or' gradually develops into an inclusive 'or'. A restaurant offers 'free coffee or juice'. The customers ask for both, and gradually they are given it, first as a courtesy, and eventually as an expectation.
Gist of Idea
An offer of 'free coffee or juice' could slowly shift from exclusive 'or' to inclusive 'or'
Source
Roy Sorensen (Vagueness and Contradiction [2001], 7.2)
Book Reference
Sorensen,Roy: 'Vagueness and Contradiction' [OUP 2004], p.112
A Reaction
[compressed] A very nice example - of the rot of vagueness even seeping into the basic logical connectives. We don't have to accept it, though. Each instance of usage of 'or', by manager or customer, might be clearly one or the other.