The phrasing of this disturbs me somehow.
um, ya.
"taken by surprise" sure does bring some specific images to mind and if the activities are anywhere close to the images in my mind, OP should be calling the police each time they are "taken by surprise".
but that reminds me of a joke:
guy goes bear hunting. First year he gets a big bear and is thrilled. Vows to return next year.
Next year comes. He is out hunting. To his surprise a big bear sneaks up behind him and taps him on the shoulder. He turns around. The bear says; last year you killed my brother. I will give you two choices. Let me screw you or I will maul you to death. Guy is not thrilled about either but obviously chooses the non-lethal activity. He then goes home.
He stews in his anger all the ensuing year and vows to go and kill that bear the next hunting season. The season comes and off he goes in search of the bear. Again, the bear sneaks up behind him and taps him on the shoulder. Guy turns around and is surprised to see the same bear and realizes there is no way for him to shoot the bear before the bear could maul him.
Bear gives him the same options as the previous year. Again the guy takes the non-lethal treatment. Again the guy goes home, even more angry than before and vows, again, to kill the bear the following hunting season.
So, the next season comes and guy goes hunting. Again the bear sneaks up on the guy and taps him on the shoulder. Again the bear gives the same two choices and again the guy takes the non-lethal choice.
This time, as he finishes, the bear says to the hunter;
You aren't really coming back each year to hunt, are you?