Mexico’s new requirement to collect a hefty deposit from drivers of all foreign cars entering from the U.S. was suspended indefinitely after one day. Officials will study a better way to accomplish their goal of reducing illegal sales of cars within Mexico. Of perhaps more pressing concern to travelers is the question of the border’s Y2K readiness. In a “secret test” at the the Otay Mesa border crossing about 40 miles west of San Diego Nov. 30, the entire computer system froze and trucks were backed up for five hours and five miles. It may be prudent to avoid crossing the border the first week of January.