many times checks will involve nothing - I’ve had countless entries without a single question asked. If asked questions, however, one of the first thing any inspector would be wary of is any form of inconsistency in people’s narratives. If you say you go to Australia from the U.K. for your summer holiday but have planned a total trip length of three days, all spent in Canberra, people will think there is something fishy, and conversely, if you say you’ve come to attend a conference but booked an RV in the Great parks as your accommodation they will want to see how it squares. If you say you are a student who’s come to party but are booked at te Ritz Carlton in Arlington, VA, something will seem odd and vice versa for an investment banker who’d be booked in a random hostel in a seedy part of town. My suggestion would always be to tell the truth and explain things as they are. This might lead to a couple of extra questions for instance on how much money you have but that will take far less time than if any official is convinced there is something that doesn’t make sense about your story but they haven’t put their finger on it yet.