Well I guess this is a case of learning something new everyday. As a admitted new DM and new D&D player I was under the assumption that cantrips were spells that a certain class knew and could cast out of habit, that other classes could cast but had to follow the spell. After reading your reply, pulling out my PHB and looking over all the spells per class. I see that cantrips do not act as spells that other classes can use. So, I'll remove my foot from my mouth and go sit in the corner now
All good! We all started out knowing nothing. I remember bribing my first dm to let my cleric learn raise dead... When clerics automatically knew every spell they could cast.