Two Alabama women pleaded guilty Wednesday to federal assault charges after a dispute aboard a Carnival cruise ship returning from the Bahamas escalated into a physical fight . The dispute started near the end of the March cruise aboard the Carnival Spirit, which departed from Mobile, Alabama. Investigators said Tonya Nelson, 58, approached Lisa Horace, 51, and her husband at Guest Services on Deck 2, to let them know they were in the wrong line, according to FBI interview summaries cited by AL.com . Nelson told investigators that she was trying to be helpful by telling the couple they were in the wrong line and pointing out that it was reserved for diamond and platinum members of Carnival’s VIFP loyalty program. Horace initially ignored Nelson’s comment about standing in the wrong line, but tensions escalated after Nelson allegedly tapped Horace’s husband on the shoulder multiple times.…