i used to do many outcalls. They most likely get a taxi- the taxi drivers don't really care and know what goes on, they drop off, leave and come back to pick up. OR they have a personal driver who drops off and leaves before pickup. Usually its pre arranged to come and pick up at allotted time or the girl gives a ring when its time. They never sit in car outside your house- thats stupid. (although one did from over 60 punts but hid in girlfriends boot) the best is when the girls drive themselves. They don't need bodyguard as having your address is pretty safe for them.
The great thing about outcall is you can fuck anywhere and on anything. With in calls, most places is just a bed. With your house you could fuck her on a desk, fuck in chair, fuck on the stairs, fuck in the bath, fuck wherever you like- cover her in cream from the fridge. You can put a porn movie on if you like and fuck whilst you watch.
If you want to be discreet, tell them to arrive casual and bring sexy lingerie and outfits with them like what i have done in the past- unfortunately one time a girl was dressed like a slut and knocked on wrong houses- shitting myself as i saw her walking past adjacent street from my window knowing she was my escort by the look of her clothes- that taught me a good lesson to tell them to bring the clothes.
Another tip is remember they take everything with them- years ago one left her glasses but only realised later but luckily that was felt with safely.