I think our chum Furry John has employed these tactic to great effect in the past (iirc).
GC
Yes it worked with the 900cc R75/6 Bmw, GC, but alternatively my latest purchase was the reverse, I was phoned and told of the dealers advert having been changed and this bike being added one evening, rang the next morning, said I was interested, drove 230 miles, paid a deposit of £1000, the dealer said it was mine and I left for home, he rang on the way home to say if I wanted to sell the bike he could get an extra £2000 for me without me actually paying anymore, I said no I wanted to keep it, collected it yesterday (another 460 miles), the dealer said he had offers of all manner of illegal/immoral ploys to sell it to other people and bugger me as I put the bloody thing up the ramp into the back of the van outside the shop, a German was hassling me to sell to him for £3000 more than I had just paid.
The "last months magazine" method only works if it is a bike that is not selling well but you want in particular and are aiming for cheapness. Some bikes only quick action means you get it.
Furry John