3 Min Read MEXICO CITY/WASHINGTON (Reuters) -Mexico’s effort to stamp out employment contracts signed behind the backs of workers has “significant weaknesses” and should be reformed, said a U.S. advisory board that monitors Mexico’s compliance with a new regional trade pact. FILE PHOTO: Workers leave after finishing their shift at the GM truck assembly plant as the company gradually restart operations at their Mexican facilities, amid the outbreak of the coronavirus disease (COVID-19), in Silao, Mexico May 22, 2020. REUTERS/Sergio Maldonado The Independent Mexico Labor Expert Board (IMLEB), which was created by the U.S. Congress, flagged a disputed ballot at a General Motors plant as an example of shortfalls in a new Mexican labor law requiring “legitimation” votes in a bid to end the widespread practice of unions and companies signing contracts without workers’ knowledge.