They are just trying to be clever again mate!
But seriously guys any other areas where you may have encountered any escorts on the street 
Okay, you want seriousness. Here it is.
A girl on the street is more vulnerable. She is getting into cars with strangers to go to a quiet, hidden away, place. She is vulnerable to robbery, rape and violence. Between tricks she has to stand out on the street in the cold and the rain and in full sight of the locals who don't want her there and may well take vigilante action against her. She is also committing an offence just by standing there and doing so out in the open in full view of the police.
So why would a girl do that rather than work in a parlour or a flat where none of that applies? Street girls do that because they HAVE NO OTHER CHOICES.
Street girls are more likely to be coercively pimped, forced to be on the game against their will. They are more likely to be trafficked. They are more likely to have mental health issues or to lead chaotic lives that make them unattractive to parlours who need reliable staff and unable to organise the things necessary to be independents. They are more likely to have drug or alcohol problems.
You as a punter are vastly more likely to be contributing to the abuse of these women by punting street girls than parlour girls or independents.
Don't care about the women? How about the people of Birmingham?
People who live in areas where girls work the streets find the detritus of the business, (used condoms, syringes and the like), in their gardens and on the streets. They have children like everyone else, and they care about their wellbeing as they walk to school in the early morning. Women and girls, (sometime very young girls), who live in these areas find themselves being propositioned for sex just because they are on the street. Imagine those things happening on a regular basis to your child or your wife.
Along with the street girls come the pimps and the drug dealers and other assorted low life's. Pretty soon the area starts to feel like a war zone. People don't come to the area and good folk stay off the streets so the local businesses fail and close down. The area becomes derelict and boarded up. Property values drop so people can't sell up and leave and the area becomes extremely unpleasant to live in.
Don't care about the locals? How about you and yours?
Street girls, because of all of the above are more vulnerable to punters forcing bareback on them or perhaps to their offering it for a premium. This, in conjunction with all of the things mentioned above makes them more likely to be carriers of untreated STDs which they will pass on to you. Taking basic precautions like visually inspecting a girl, which you would do naturally in a punt, is almost impossible in a car parked in a dark alleyway.
It is quite possible to infect your loved ones with life threatening incurable diseases without even knowing that you yourself have been infected. Using a condom isn't always a fail safe method of protecting yourself.
Street girls, by definition, are likely to be more desperate for quick cash and are more likely to rob you. Robbing you is easier while your pants are down, in a confined space and when your mind is elsewhere.
If that wasn't enough Kerb crawling is illegal and you can be arrested for it. Usually after arrest and charge your details will be published in the local press and letters concerning the case will be sent to your home. Your wife and your employer will know that you have been arrested and charged for a sex related offence. This too may have some impact on aspects of your life.
So, in conclusion, when the guys here take the piss they are indeed "trying to be clever", but they are doing so secure in the knowledge that the person asking the question REALLY REALLY isn't. People here may or may not know about the street walkers of Brum, but I would imagine that they aren't telling you about any of it because they already made some assessments of you and your capacity for rational thought.
The jokes from some of the guys here are perhaps a blokey way of saying "Wise up fool!"
I don't know about them. For my part I was really just taking the piss.
