When I was going to read the tab for suffragette city by David Bowie, and Whole Lotta Love by Led Zeppelin, it says that the tab is blocked. Why is it so?
"This tablature has been made unavailable in your country at the request
of the rights owner."
Quote by wizards?
I want to buy a 7 string guitar, and tune it to Cabbage.

That was on topic, I swear.
Some stinking lawyer has seen a way of screwing money out of people and stifle creativity in people. Or its some one whom hates guitarists
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There are dozens of threads already talking about this. It's a legal issue so there's nothing UG can do about it.

If you search for the older threads about it though, some of them tell you how to get around the problem.
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You know, this is a contentious issue no doubt.
But as a musician, I must say that these songs are in huge circulation and can easily be learned by playing with other musos. Alternatively, cruise some lawn sales (garage sales... whatever they are called in your corner of the world) and buy all the dog-eared music books you can! David Bowie books? There are hundreds of releases, and some are on eBay for about $1.60! Led Zeppelin are the same. There is sooooo much printed music out there that is easy to get your hands on. Just because a tab is blocked on here does not mean you can't get it; it just means you might have to leave the house, or go to a different site... or even pay for it.
I have no issue paying for music. Someone wrote it; the deserve some recognition and money for it. What I DO have issue with however is when a tab is blocked, but that band does not have sheet music available for purchase anywhere in the world. In these cases, I take great pride in the challenge of sitting down with my ipod and guitar, and unlocking the mystery of their songs. I become a better guitarist/musician for the experience, and I now know something I didn't before. But it's not the end of the world, and it's NOT UG's fault. Hell, I'm sure lawyers would rather MAKE money than tell people what they CAN'T DO; I imagine they'd much rather sites like this break all the rules, because when they comply, their is no law suit, hence lawyers only make their retainer; what they would have made eating a kebab instead of sending letters to UG saying 'take this down, take that down, move this, toss that.' No, there's no money in that kind of lawyer-ism.
So, can't get it here? Look elsewhere. Can't be bothered leaving the house? Check out eBay or Amazon. BARGAINS TO BE HAD, peoples!