I have similar problem, but it is due to other members of home who fond of guest, if I was alone no   unwanted guest can dare to intrude   my home. Certainly, it can be solved by understanding with all members of the family, and come out with policy. But it can be applied to new guest.
A palmist, after examining the fortune lines of a person said “I am sure your problems will be resolved in a year. The person replied “are you sure sir”.
“No the problems are not resolved, But you will used to the problems”, replied by the palmist.
I am sure Swetha’s problem will be resolved soon.

I like Spiritalk's approach. Just pretend you're leaving or getting ready to... put on some make-up in their presence like you're in a hurry and excuse yourself, cuz you have to put on that nice blouse cuz you obviously cant do THAT in their presence... haha. Perfect!

Like the palmist joke, but can't bear the thought of having to get used to other people's bad habits! ;)