Well I've just done as you suggest and can only see that suggestion made specifically about Biggin by one poster other than you and then without much in the way of supporting detail.
Whilst going through the thread, I came across this comment of yours:
No-one is suggesting a flight plan typically negates the need for PPR elsewhere. Only at Biggin.
Actually, to give just two examples of airports I use frequently, at both Cambridge and Prestwick it works exactly like that.