Like a good portion of the game, there are no definitive answers. The Sampans are supposedly capable of calling "home" and placing your submarine at a certain location within a certain amount of time. So, if they see you for say 30 seconds, a contact report has been sent as to your whereabouts. Depending upon where you are, you might see a plane or a Chidori rather quickly.
If you go to do it, do it stealthily, fast & deadly. In other words, sneak up on them, battle surface, and take them out fast. But take no damage of your own. Sometimes a bit tough to do. Some skippers attacked them, some let them be. I used to take them out, but I encountered one that had a 20mm cannon once, and took casualties as well as quite a bit of hull damage. Had to come back in with no ships sunk, all my torpedoes still in the racks, and three wounded. Did not look good on my record...
Now I leave them be, giving them a wide berth, unless I ~have~ to take them out. If in stock, you might be OK, maybe finding a few with machine guns, but in some of the mods, they can be deadly if you're not careful. You will get renown points (20??) for taking them out.
