People say a lot of things... nobody has notified the cycling community or the park apparently that mono cliffs has banned bicycles. As long as you're within the park limits you should be ok. Like you said there are no official signs or anything posted either.

My bet is you ran into some Bruce trail Conservation type people. Canada's sierra club. Haha, anyways ride with care... follow the trail etiquette rules

http://www.orangeville.com/opinion/l...ike-riders-bad