Drug dealers on pirate radio
Okay, to answer the drug dealers question.
A big pirate operation will need funding. This comes from advertising, but in a roundabout way; event promotion, sort of like product placement. Local shops and services would be very, very dumb to advertise on big-name pirate radio because they'd get fined pretty much straight away.
For the larger pirates, how it works is that an organised crime gang will control the supply of drugs in particular nightclubs. Any rival dealers will get bounced out, man-handed to the polis or just plain beaten up, whereas dealers from the "in-house" gang will get waved through the door and overlooked by the bouncers.
The big pirate radio stations then get paid to promote the nightclubs controlled by the drugs gangs. Sometimes there's also negative advertising ("dissing") of rival nightclubs.
The gang control can be either directly through links with the nightclub management, or it can be done by, ahem, "persuading" the bouncers. Now the bouncers do get criminal records checks, but there's essentially a never-ending supply of clean-skin bouncers with no record. Drug dealing is incredibly lucrative so they have plenty of funds to tempt even the most saintly of broken-nosed weekend rugby wannabees.
You've got to bear in mind that even the big-name pirates will be essentially hobbies, labours of love by the DJs and engineers. It's their baby, they'll do anything to keep it going. And especially with the engineers, they tend to be geeks with not much common sense about how organised crime works. When faced with the need for a couple of hundred quid to replace a transmitter, or the need to have a bouncer guarding the studio door, they'll accept offers of help from strangers not because of the profit, but because that's what needs to be done to keep their station going. They're idiots, and they're still guilty, but they never went in to the pirate business to become rich or to promote drugs.
For the smaller pirates, the ones which don't operate regular or frequent hours, they'll generally have no other criminal connections and will be run by some independently wealthy electronics geek. Typically these will be teenagers with rich parents and a little too much pocket money or a lucrative part-time job, often from out-of-town country villages or posh suburbs. These lads will simply see the inner cities as places with lots of listeners and lots of tall buildings, the concept of crime won't even figure in their mind - they grew up in a place which didn't have crime, it's something they don't need to think about. For them, sure, you *can* just wire up an MP3 player to a biscuit-tin TX, shove the aerial up a tree on top of a rural hill and scarper until the battery runs out, but sheep don't have radios and tractor drivers only listen to Radio 2, so in all likelyhood you won't get many listeners and thus have nobody to brag to. Whereas an inner-city tower-block will have a power supply and thousands of keen listeners well within range. Then, at some point, an organised criminal ring-leader will spot some potential and make the lad a very, very interesting offer. If the lad is sensible then he'll correctly figure that if he just goes back to his home village and keeps out of the inner city for a few years, or even better buggers off to university on the other side of the country, he can just ignore the offer. Otherwise... he's starting down the path to real trouble.