I have been recently asked to furnish an "affidavit of support form" for the INS
(form I-864, http://uscis.gov/graphics/formsfee/forms/files/I-864.pdf)
for her. She is being sponsored by her husband (a US citizen) here,
but they are falling short of the federal poverty line.

I have read the I-864 form and it appears that the commitment that is
being made is limited to reimbursing the government or any private
agency that provides Federal, State, or Local means-tested public
benefits for any such benefits given to the sponsored person.

Note that I have read some of the previous answers to similar questions:
http://answers.google.com/answers/threadview?id=432919
http://answers.google.com/answers/threadview?id=249196

The question is regarding the amount of potential risk/liability
incurred by signing the affidavit of support. In other words, what the
worst-case financial scenario could be. From reading of the previous
replies and the referenced documents I understood that

(1) I would be liable for things like welfare programs and Medicaid,
etc. Is there anything else (like Medicaid) that could potentially be
a large or unbounded quantity.

(2) The sponsored person would not be elegible for means-tested public
benefits for teh first 5 years, so my exposure is limited to the 5
years following that.

(3) If the sponsored person were to apply for publisc benefits, my
income would be "deemed" (i.e. considered) and therefore she would be
disqualified.

(4) Is she was in need, she could sue me to obtain the level of
support spefied in the affidavit which would be aroung 125% of the
poverty line.
 
Are these interpretations (specially #4) correct. What I am looking
for is breakdown of what the worst-case situation would be for the
sponsor (me). In addition, any opinion or insights are appreciated.
Thanks,