Are there any legal loopholes to circumvent this...?
well if you are in US, and working for some company, you will have to show pay syubs, I am still in India, never landed in US, and my Initial employer was unable to give me work..for more information send me personal message.
Yes transfer will make A visa invalid.So you will again have to do a transfer from B to A..
If so, what if new employer again has some problem in giving me work ? I am out of status ? So, how much sure are you about this ?