(IDEX Online) - Jewelry salespeople in the US are being urged to take extra care, after one was stabbed and two others were targeted by criminals within a week.The Jewelers' Security Alliance (JSA) says it's important to check nobody's following your vehicle, and to take "evasive driving techniques" if necessary.A traveling salesperson was stabbed twice after four males smashed their car window and grabbed a bag of jewelry in Delray Beach, Florida, on 28 April.Three days earlier custom jewelry pieces were taken from a vehicle in Santa Clara, California.And on 22 April, a jewelry salesperson was struck on the back of his head and had his bag stolen as he left an hotel in Orlando, Florida.JSA is making these recommendations:1. During a day of sales calls, and before returning to one's hotel, home or office, salespersons must always be alert to whether they are being followed. Take a few minutes to engage in evasive driving techniques: circle the block, drive slowly, make a U-turn, and see if you are being followed. 2. Never leave jewelry in an unattended vehicle. In addition to the loss, most jewelry insurance policies don't cover losses from an unattended vehicle.