Checking in late will increase the odds you will miss your flight.

Day to day operations seldom result in bump opportunities. Out of the ordinary situations such as weather and mechanical often result in bump opportunities. The key is to be prepared to take advantage of such opportunities if you so desire. The information provided in ExpertFlyer and the information provided by the airline web site are good indications of the status of a flight. Ideally solo traveler, carry on luggage only, boarding pass in hand, at the gate 1 hour prior to departure to volunteer, remaining at the gate, alternate routes determined in advance, etc.