Why would you want to open up a bank account if you only had a tourist visa?
Well, perhaps you want to buy an apartment in Peru, which probably isn't a bad idea since the Peruvian economy continues to be on the rise and mortgage loans are usually from 15-18%. Now I don't know much about economics, but it does seem plausible that if EVERYBODY ELSE thinks that the value of their property is going to rise in excess of 18% (otherwise why would they agree to the loan) that it can't be all that bad of an idea.
Oh, another reason you might want to open up a bank account in Peru is so you can play online poker since most stars like pokerstars.com require a foreign account...because of the bible bashers or something....or maybe you just want to make a one time transfer to Peru for the duration of your trip so you don't have to get stuck paying the 5$ transaction fee that you get stuck with every time you make a withdrawl with a card (ATM fee, foreign currency fee, etc.).
There are probably a few unethical reasons to open up a bank account, but there are enough legitimate ones that it should be a universally legal and accepted practice by Peruvian banks. However, it isn't.
Still, not to fear since Interbank will allow you to open an account...as long as you open it in one of their Supermarket counters and NOT in one of their regular branches (this was the rule at one time, I don't know if it's the same anymore...it seems so frickin' absurd you'd think it wouldn't be, but if there's one thing I've learned in my life it's that the world rarely makes sense).
The end result is that if you get rejected at a bank, all you have to do is walk down to the nearest Vivanda and ask there. But before you make the trip, make sure you bring TWO forms of ID (a passport and a driver's license would be fine) and voila...no more need to carry around your money in Peru.
Incidentally, isn't that an awesome picture? Those red lights behind that car are eerie, and what do you think that shadowy woman in the high heels is doing? Is she walking the streets for money? Hanging out at the Interbank looking for a loan? Are there six hundred guys who have fallen in love with her just from looking at this picture and who have vowed to come to Peru to meet her? If there are, please let me know. Come to Peru and document your journey and send me the photos...I'll publish them...you can be assured of that!