Wear heels and stay in your seat. You WILL get caught because people don't take kindly to someone trying to squeeze in their row. You won't be able to stand in the aisle depending on the concert so you'd have to try to stand in a row that's full. Or try to sit in a seat you think is empty only to get kicked out when the seat owner comes. I've been in rows where rude people try to squeeze in, thus squishing others together and believe me it never works out for the best. I'm 5'9 and I never go more than a few rows back on the floor.