Gene,
I may not be typical but I usually have my checkbook at the ready whenever I am close to deciding on a buy. In addition, my bank is expecting a call from the seller. I encourage the seller,through his bank,to call mine and get confirmation that the check is good. The stress level for the seller is considerably reduced! Any decent banker knows the procedure for assuring their customer the check is good.
For me,a deal killer,is to check the FAA Database and find the "owners" name is not on the registration, only sale reported. When an aircraft has been in a persons possession a sufficient time for the paperwork to clear and it hasn't,I assume I am dealing with a snake oil salesman. The day I write the check is the day the registration and bill of sale are sent to the FAA. That of course means I will get the pay up letter from the state in short order, but that is the cost of doing business. Dealing with sidewinders is a tedious task I strive to avoid.