It's common knowledge that people find exiting at the same place they entered comforting. And we being people... we usually go for the easiest, most comfortable option.
So... If you ask someone for an ongoing favor, they are likely to bow out in much the same way they got into the situation in the first place.
If you are a pastor, and you ask someone to participate in a certain ministry, chances are they will do so, and when they want out, they will come and see you to explain they need to stop now.
If your church has a committee to choose ministry leaders, anyone who says yes will usually wait until the next committee session to get out of it.
If someone just starts doing something without telling anyone, chances are big that they won't tell anyone when they stop doing it either.
This is true for relationships, retail, travel, debt .... but not children! (thankfully!)
So know this information. And sure, use it to your advantage, or better still, spot people who need a way out, and be as courteous to them as holding the door for someone behind you.