Check out the case law about Mcdonalds v Quality Inns (re: McSleep Inns)
Mcdonald's was able to show that there would be consumer confusion DESPITE Mcdonald's not doing hotels nor Mcsleep inns not doing food.
As a result, Mcdonalds basically has an open trademark enforcement on "Mc-" whatever.
While I'm not fond of the judgement here, it was nonetheless decided thusly, and contradicts your otherwise accurate (so far as I know) statement. (And to weaken my own point, I believe Apple lost a similar case about i<whatever>, so nothing here is clear and reliable.)
Mcdonald's was able to show that there would be consumer confusion DESPITE Mcdonald's not doing hotels nor Mcsleep inns not doing food.
As a result, Mcdonalds basically has an open trademark enforcement on "Mc-" whatever.
While I'm not fond of the judgement here, it was nonetheless decided thusly, and contradicts your otherwise accurate (so far as I know) statement. (And to weaken my own point, I believe Apple lost a similar case about i<whatever>, so nothing here is clear and reliable.)