Having hauled 400+ tons of illegal goods at a time into many locations I can say, without a doubt:
1. Being scanned can certainly suck.
2. Don't get scanned.
3. Silent Running is not fool-proof, but it can help as long as:
3a. You keep your heat down
3b. You don't speed.
3c. You speed like hell.
I have no problems getting into or out of stations, in a Type-9 with D-grade thrusters (G3 dirty modded) absolutely stuffed full of illegal goods without getting scanned.
At one point during the Parun CG I'd either made so many runs they didn't even bother to scan me any more, or they just trusted me that they'd stopped scanning me - dunno, but they did just stop trying.
If you're going the Fly Casual route - you have to do just that - fly casual. Don't speed, don't boost, don't make any erratic movements. Don't bump into anything and don't try to "shortcut" through the habitation ring of stations. Silent running helps tremendously, but you have to keep an eye on your heat. Keep it cool, stay cool, and all will be well.
If you take the Speed-Like-Hell approach - it's full pips to Engines, boost like your life depends on it, and frame shift as soon as you break mass lock. Or if you're coming in to a station - silent running can still help, but you need to take a slightly different approach - line up your approach, drop a heat sink, go Silent, boost like mad towards the toast rack, request docking at 5 Km, drop another heat sink if you need, and shoot through the slot - then turn Silent Running back on again.