Very sorry to hear about your problems on Stiperstones. we were there on Wednesday, and have been many times before, and have never met a Ranger or had any problems - apart from dealing with questions from interested passers-by.
However, in case this turns out to be a ‘local’ issue, it is worth reminding activators that the National Trust wardens on Pole Bank (G/WB-005) are much more often encountered and they will move you on if you are operating on their land. This problem can be easily avoided if you read your map or GPS carefully as their is a portion of land that is outside their boundary (check the red lines carefully! Basically, if you are walking up from the Shooting Box CP (the highest one with a tumulus beside it) towards the trig point continue the ascent (and a bit of descent) until you see the fence beside you on the right. From this point (or soon after) the land on your left (the Church Stretton side) is NOT NT property. Either push through the heather or walk on until a crosspath cuts the track and an old track will be seen sharp left which takes you into this area almost parallel to the way you have walked up. Wander along this and set up where you will or drop off a bit lower on the the Eastern side if you are a less hardy HF type and want to snuggle down!
Another tip is to go in pouring rain (like last Wednesday afternoon) and you won’t meet anyone but it is still good to know you are on ‘safe’ ground. No problem finding this weather on any day, except Sunday, in the following week according to our forecasts so plenty of scope!!
Viki M6BWA