Its pretty much a 24 hour culture these days. If people want to work all hours they can do. The idea of stealing from others or undercutting people in full time employment is redundant. Its just business and it goes to whoever can do it. If you go down the route of declaring your earnings you effectively announce yourself as self employed and this will have implications on the way you have to manage your income. You can do no better than arrange a meeting with the local Inland Revenue office to find out where you stand. The advice is legal and free.