Definition of hit and run
Hit and run or hit n run is the reality of players playing heads-up. When a player wants to play heads-up poker, he takes a seat, waits for his opponent and starts playing when he arrives. Hit and run is when you play a few hands of heads-up poker, win 1 or 2 pots, win and quit without warning. You play a few hands, win a little and quit.
The hit and run, legal but not moral
When taking a seat to play one-on-one with another player, if you want to be cordial, you can chat with them to agree on how many hands or how long you want to play. "I'll only be here 15 minutes" or "We can play 1,000 hands minimum". Leaving without warning can be frustrating for the other player. Especially when an opponent is new and very aggressive, you may think you'll study him a bit before adjusting and after 10 hands he's gone. Always make sure you agree on the number of hands to play with your opponent before the game starts. This will give you a better reputation.