Modern times are far different from the days of old in the rural towns and cities of America during the early part of the 20th century. Life for the Negro was particularly hard. If you were able bodied and strong, then there was plenty of work around at very poor wages and some men didn't want this. Others were disabled in some way and it was common to see blind guitar players on the street singing for pennies. It wasn't unusual for a man to play for many hours for almost nothing. The legendary blues man Blind Lemon Jefferson was explained how he would play on a local street corner and after almost a full day only had enough money to buy a loaf of bread.
Others took to the street to earn money, but also to give a message to the passers-by. One such street singer was Reverend Gary Davis, who sang his Gospel spirituals on the streets of Harlem in the 1930s. Blind Boy Fuller would play accompanied by harmonica player Sonnie Terry outside tobacco warehouses at the time when a work shift ended, hoping for a few cents from the working men on their way home. Yes, the tradition of performing music on the streets is strong, whether it be guitar, saxophone or other easily carried instrument. Some enterprising people have even pushed along small pianos!
After the folk-blues revival in the 60s, young guitarists became interested in learning guitar and once again took to the street to perform. Sometimes because there was nowhere else to play, and now and again hoping to make a little money. Many people saw the activity as very romantic and were pleased to follow in the footsteps of those solitary legendary figures like Son House and Robert Johnson. It's also a great way to practice your tunes. Not too many people stop to listen unless the artist is very good, so it's possible to play the same tune for a long time, introducing variations and generally getting better and better.
Many cities in America and Europe just don't allow busking any more, or have introduced a licensing system, which most musicians can't be bothered with. Cities have other rules to dissuade the faint hearted. Amsterdam restricts the activity to certain areas at certain times and definitely no amplification. Other cities tolerate it and often it's up to the individual policeman if he moves a musician on or not. In Spain, he run the risk of being fined and having his instrument confiscated - the worst thing that can happen to a musician.