The pro­hi­bi­tion on smok­ing set forth in Sec­tion 6–35 and 6–37 shall not apply to a pub­lic place or place of employ­ment of a tobac­co deal­er that per­mits cus­tomers to sam­ple tobac­co prod­ucts on the premis­es of the tobac­co deal­er, pro­vid­ed that smoke gen­er­at­ed by smok­ing on the premis­es of the tobac­co deal­er does not infil­trate any oth­er enclosed pub­lic place or place of employ­ment.  For pur­pos­es of this exemp­tion, a tobac­co deal­er is a retail­er whose prin­ci­pal busi­ness is the sale at retail of tobac­co and tobac­­co-relat­ed products.