What's suspicious about that? I ask based solely on the seat map any time I'm not in a hurry to get where I'm going (usually home). If I'm checking luggage, I say to the TA "does this flight/either flight look oversold?" If they say yes or I'm flying with carryon only, I waste no time going to the gate and usually catch the GA then they arrive. Though if I'm looking for the bump, I check availability on subsequent flights- if I'm in F or an exit row, the voucher's gotta be big for me to take a bad seat on a long flight.