Perhaps it's not in the spirit of giving expecting nothing in return, but so be it - it's how I think and feel.
I have three children eighteen and older living under my roof - all my sons. Although I recognize their ability and right to make their own decisions, regardless of whether or not they are in line with my wishes for them, I do have the power to put conditions on those actions. Even if they didn't live here, if they still required support from me - whether through financial support or insurance coverage - I expect to know how they are using that support. If they borrow my car, I expect to know where they are taking it and if anyone else will be with them. As they are living under my roof, I expect to be consulted when they stay out late or all night - meaning, I want to know where they are and how I can reach them.
We call this respect in my house. You may not live with your parents, but you do benefit from their support. If I were your mother, I would appreciate respect from you in the form of you informing me before I have to find out through a third party that my support was required for something I would have concerns about. "Sins of omission" - you not telling me about it - amounts to a lie in my eyes. And in my family, lies are always worse than the truth.
My kids say their father and I are strict, but they also don't complain (much) about it. As a result of this expectation of honesty and respect, I know which of my children have drank alcohol, which have tried drugs (and which drugs), and which are sexually active (and the one time they choose not to use protection). In expecting this respect, I also have to be willing to hear some things that most parents don't want to hear, but I'll be damned if I'm going to let my hangups and aversions to "TMI" put me in a position where I cannot be helpful to my children because I don't know what's going on with them.
I know I went into more depth than required, but this is something I feel strongly about and I've avoided replying to your initial inquiry because I knew where I'd go with it. Some folks don't like strong opinions - but you asked.
Em, quit lying to your parents. They've provided you with support, and it's disrespectful that you're keeping this from them.
Peace & Love,
Sugah