When I test drove my Elise, the seller asked that I show up with a Cashier's check in my hand. I showed him the check, we set the check on his desk, and he hopped in the passenger seat. I test drove the car through a mixture of city/highway driving. If I had not bought the car, I could have taken the cashier's check back to the issuing bank, and deposited it back in my account. But a cashier's check shows seriousness, and availability of actual/real funds. It is not a bad stipulation to expect a buyer to have one on hand before the test drive. The check also covers you if the car gets seriously wrecked during the test drive.
Storm titanium 2005 Elise with carbon fiber spoiler, BWR sway bar, BOE toe links, gPan2, LidBone, sector 111 wheel studs, Grey RAC Monolite wheels with toyo R1R, Team Dynamics 1.4 with Hoosier A6/R6s, Katana2 Supercharger, ECU with 265 flash. PPE headers w/decat, CEL angle eliminator, Silent touch catback, Rear Panel Eliminator, HKS intake, V2 fuel tank, Walbro255 fuel pump. HID lights.