Sure, why not? Many fiddlers have some classical training. The ones I've heard do carry over their training though. Sometimes they sound a little too "correct" and lack "feeling". I have seen a some grow out of that and become great fiddlers though. My ex bandmate Andy is a good example; classically trained, then fiddled Bluegrass with us for several years, moved out West and then Nashville. Played the Opry with Darrell Singletary just last week or so and recently went overseas with him to perform.