Absconding is the practice which happens whenever members of a tribute alliance take items and articles from each other without their peers knowing. In The Hunger Games trilogy, there has been no known use of this strategy. However, it's easy to assume that in some unknown Hunger Games, this strategy has been used.
Advantages and Disadvantages
Absconding is often used by tributes with traitorous nature. They account themselves as part of an alliance, allowing access to their possessions during active Hunger Games. This could be very useful to tributes who are not good hunters or gatherers, or who didn't acquire anything at the Cornucopia bloodbath. However, using this strategy could be deadly, as you reveal yourself as a traitor if you're caught.
In The Hunger Games, after the Career tributes' supplies had been blown up, Katniss speculated on allowing Foxface into her and Rue's alliance, but dismissed it, perhaps thinking that Foxface could have taken her and Rue's supplies behind their back.