when someone does a chargeback...
 

...does visa or mc or whoever require the cardholder to get a new card and/or number? i mean, with the chargeback system, i would think that they _should_, since the cardholder is basically saying someone stole their cc. anybody know about this for sure, or used the chargeback before?

Usually when they say their card has been stolen they'll get a new #, but the can still chargeback if the product is not as described, or if it never arrived, etc...then they usually wont change the #

A chargeback for unauthorized use does not necessarily mean the card was stolen.
Many times, it as simple as an unrecognized merchant name. I deal with many customers each day who have no idea what the merchant is, until I tell them the merchant category (Sir, it was a pharmacy... Oh yeah, I remember I picked up my pills!). Other times, it's a customer who has someone else on the account (Sir, did you ask your wife if she did it? My wife would never shope there! Ask her anyways and call us back... 10 mins later, the customer lets us know his wife was buying a gift for someone.) etc etc.
Also, billing errors can happen. I had a customer calling to dispute charges for pre-paid cellphone time. Turns out someone else had a similar card number with the exact same expiry date as his, but he accidentally transposed the digits (ie hit 9610 instead of 9160) and was billing this other guy.

So no, the card does not get cancelled (unless the customer absolutely insists on it).

Kill anyone attempting to chargeback. It's ettiquitte

Why? When someone buys a membership then charges that shit back you should be submitting those to a collections agency.

what agency?

you need to send man around to home with big stick.