They've been busy rewriting the enforcement rules over at the Customs Service to cope with dramatically increased imports and to clean up some legalisms on procedures for boarding and searching American ships on the high seas.

Just this week, Customs authorized its district directors (there are 46 of them, covering 300 ports of entry) to examine fewer incoming shipments. Previously, at least one package of every invoice and one of every 10 packages of imported merchandise had to be opened and examined. That was fine in 1960, when imports totaled $14.8 billion. But by 1980, with imports at $245.9 billion, the requirement slowed cargo-handling to a crawl.

Now district directors can authorize the release of merchandise without examining it, something they previously could do only with the specific approval of the secretary of the treasury. Other more selective enforcement techniques can be used to assure that the proper duties are collected, the rulemakers reasoned. Customs' widely publicized manpower shortage "is not an overriding concern here," according to Victor Weeren of Customs' Office of Inspection. "This is not like clearing passengers at new international airports . . . We think this is good for Customs and good for the importer."

Meanwhile, on the seas, Customs and the Coast Guard are busy fighting the influx of illegal drugs, but a Customs regulation prohibits its agents from boarding an American vessel unless there is probable cause to believe something illegal is going on. The Coast Guard, whose officers are also customs officers, had no such restrictions and the federal courts held that there was no law saying Customs had to be restrained. So Customs has proposed removing that restriction from its regulations.