Visa on arrival at Dubai Airport is very strict now. They will ask for your ID and if the profession is not coming under the category they might not allow you to enter. I have two friends working in our Company and both of them are having Managerial post but the profession in their ID is not Manager. They used to go to Dubai with visa on arrival showing their prvevious entries. Recently they were warned by Dubai Airport Immigration that either they should change their profession on their ID or they should apply for a visa in advance if they want to vsit Dubai.