Hi MM,
I have been to a few Pantos with friends at the Harlequin Theatre in Redhill, (yes I do get about) and it has had "stars" like Vicky Michele of Ello Ello fame. I would say in general the modern panto scripts have gone the way you have described, why? I have know idea. Its suppose to be for kids aye BIG WANS too like me. I like live theatre in many guises.
However, I can see why your sister was disgusted, and a letter to the theatre would do know harm IMHO. Even in some of the West End shows, inuendo is more prevelent that it was in the past. Ok, I am nearly the wrong side of 65 but with I like to think a forward thinking mind, but to use smut for humour IMO is not needed. Personally, I blame the scriptwriters and the producers.
Iain.