As unpredicatable as it seems getting Visitor Visa for parents, My understanding about it is that
- if your parents are educated & mid 40's -50's ---NO
- if your parents got rejected first time, chance in 2nd & 3rd try ---NO
- whether you sponsor or they sponsor back in home, what you do here in US is (I think) relevent--might play some role
- If bank account shown had 20 thou couple of months before you apply and has 2 mil now---NO
- if your parents really wants to sneak here..wanna work & make some money (seen that) ---HELL NO !!!