If a person is unable to use their tourist B1/B2 visa in the 6 month period that it was approved of can they be refused a reapplication/reapproval for another one at a later date? She is unable at this time to show the embassy that she has the funds to not become a financial burden or stranded while visiting friends in the U.S. The embassy won't release her visa or plane tickets unless she can show that she has the money for her stay in the U.S.
So if you get really sick then you might get banned from the US? No, it doesn't work that way. A past visa does not count in the current application. Refusal of entry or overstaying do but using or not using a past visa doesn't.
First I got a multiple entry 10 year B1/B2 then I got a single entry visa and I was afraid to apply again because I thought it will just go down and I will be refused but I got another 10 year one.