Those people are irrelevant. They do that even with their closest friends because they all seem to be intent on not getting screwed. I'd rather share and gift extremely liberally, to the best of my abilities, among my circle of friends and even far acquaintances. Are there freeloaders in economic terms? eh, sure, but a lot of that is income dependent as well. But mostly what goes around comes around and a lot is going around -- velocity of gifting is > than velocity of money which is great. But then again I'm a small-l libertarian socialist.

>However if you're not my friend, I have no reason to take financial risks for you however small.

Technically that's not true. In the cases of con men, social engineers, and manipulators "giving free stuff" is a common psychological tactic to gain leverage over others. I.e. the sub prime mortgage scam bubble of 2008.