More than 150,000 spectators will witness a heightened security presence at tomorrow’s Kentucky Derby – the largest and highest-profile U.S. sporting event since last month’s bombings at the Boston Marathon.

USA Today reports that electric wand searches of patrons and a fresh ban on coolers in the infield of Louisville’s Churchill Downs will be implemented, but the article also states that stadiums and entertainment venues rely on “low-paid, part-time security guards with spotty training and even criminal convictions.” Turnover is high for these officer companies – officials say guards don’t stay on the job for more than a year or two.

Twenty-three states do not require applicants to complete any training.

This year, California has revoked 154 security guard licenses, often because of criminal convictions discovered after the license was issued. Florida has revoked an average of 350 licenses annually for the past five years for the same reasons. Seven states require no security guard licensing at all.

Some venues have used “event staff” employees in security roles, including performing bag searches and controlling access to restricted areas, USA Today reports. 

Israeli security experts, who have analyzed the Boston Marathon bombings, noticed that security volunteers at the finish line were watching the runners, not the crowd. The USA Today article remarks that, perhaps if guards trained in crowd control and intelligence gathering were being used, the bombings could have been prevented, or casualties reduced.