There are many cases of keys being stolen from the house (fished through the letterbox for example), but only a handful of cases where the burglar has actually threatened the householder. (a number of ex-police on the T6 forum concur that is quite rare as the syce of the common thief won't stretch to confrontation)
Lots of Calis are left at home when owners are at work and there is a risk that the keys could be found and the vehicle is taken following a break-in, but if you are not there they will not get the code.
You might drop your keys in a car park one day and return to find it gone. With the ghost, you might be stranded until the spare is recovered but at least it is not gone.
As you say there is always a "way" the official-looking tow truck method will always win, but on a scale of what is actually achievable, it is low on the list as not many opportunist thieves have a tow truck.
Every owner has to do what helps them sleep at night and assess their own situation and what lengths they want to go to.
Personally, I have
- Glass break sounders in the Cali and on the patio doors (cheap but a loud deterrent) as this might prevent possessions stolen if the glass is smashed in a car park.
- Patio doors are double laminated.
- Ghost fitted
- All keys are kept in a key safe mounted with through-wall threaded bar, the key safe is also visible through the glass of the back door so that any would-be thief will see that and realise that there is no point breaking into the house to look for keys. etc.
I build a mental list of the likelihood of each method of theft and cross off the easy ones with my list above.
There are other easy precautions I can't do, like blocking in the Cali or having a pull up post as I don't have a driveway, but these would be on my list if I had one.
You have to balance the method with your day to day use etc. Turning around the seat and pulling on the handbrake is another simple trick that would stall a common their who found your keys, but would fool a targeted theft and you will soon give up doing it if you drive it regularly.