I can confirm that what both David and Paul have said has also been introduced in Hubei and is being rigidly enforced as of the start of this semester.

I am at a high school on the outskirts of Wuhan. I renewed my contract at the same school from last year and last year had no issues with having guests (male or female) stay over. This year, on return from the summer break there was a big notice clearly stating no overnight guests allowed and a letter under our doors requiring us to sign it and return it for their records.

I did query this with our Foreign Affairs Office and they said they had been instructed to follow this rule by the local PSB. No debate, its the rule so follow it attitude.

In the summer security cameras have also been installed and point at all of our doors. Again, apparently a PSB requirement.

There is not much we can do about it but it does seem to be being ramped up this year. A friend in Hefei also reported similar issues. It seems like China is returning to the dark ages in certain respects!