I always finish my emails with どうぞよろしくお願いします。I guess in the context of an email in English it could be akin to saying "Cheers" "Regards", so I unless I put write どうぞよろしくお願いします, I will be worrying that I was being too informal to that person. 

When writing an email in Japanese, is there an scenario when finishing with どうぞよろしくお願いします would be considered as being out of place or context?