I love Linux and I think a lot of my non-technical family members would benefit from it, but I am not as brave as you. The danger with messing around with someone's computer is that you are basically taking ownership of all tech problems the person may run into. It's like the "You break it, you buy it" rule. The person may seek help from another tech geek, but as soon as that geek finds out they're dealing with a "weird" Linux system, they're going to run away from it. You are effectively volunteering to be 24x7 on-call tech support for the people whose laptops you've installed Linux on.