I wouldn't worry about cat flaps or letterboxes either.So, maybe you'd get a couple of drips go in sometimes...but as a load of them are out at work anyway, by the time they get back, any little drips would have evaporated anyway...it's pure water, it doesn't leave marks...not even on a carpet. It's not like you are going to aim the jets through the open flap...
If it's an enclosed porch with a glass door, or large pane of glass in the door....then just get an old rag and give the floor (tiled ?) a wipe over. Pull the mat (if there is one) away a few inches, clean, wipe round, push the mat back !
The only real problem I've had with a pole, is on some houses round the back, the window over a deep , wide flat roof extension. I can reach them at an angle mostly with the pole..but I can't do a good job.
For these, I have to get the ladder out for access reasons, climb up onto the roof, taking the pole, and do it from there.