Normally, jurisdictions that put straight-ticket devices on general election ballots never give independent candidates a straight-ticket device. But, at the November 5, 2013 election, Luzerne County (Pennsylvania) did give independent candidates a straight-ticket device. There were only three independent candidates for any office anywhere in the county. As a result, one independent candidate, Rick Williams, appears to have been elected to the Luzerne County Council, and chances are high he would not have been elected if the device hadn’t existed. See this story.
Election returns show that 5,956 voters used the straight-ticket device for the Democratic Party; 3,861 used the Republican device; and 758 used the independent device. The normal rationale for putting a straight-ticket device on the ballot does not really apply to independent candidates, because almost by definition of “independent”, independent candidates are likely to have any political views and may have nothing in common with each other.