My concern isn't so much with intention. If I had a source of income I would gladly tithe the full 10% every month. And it's not really about guilt. I don't feel guilty about not tithing because financially I'm not able to.
My check, technically, is Social Security Disability Insurance and is not considered a source of income by the government (and not by me either since it's barely 5% of what my income was before I got sick). It's not taxable, hence the question remains of tithability, if that's a word.
And my situation isn't going to turn around anytime soon. My disability isn't going to go away or get better and the best my doctors can say is that for the foreseeable future I will not be able to work.