So, if I'm a juror and have been paying attention, here's what would stand out to me and what I would want to know:
1. Jodi has engaged in weird stalking behavior in nearly every relationship she's had.
Bobby -- after Bobby left the library computer, Jodi took Bobby to his friend's house, and then returned to the library, where she accidentally hit the back button on the library computer and happened to bring up Bobby's hotmail account -- at which time she proceeded to actually read the emails in his account. She then printed off the emails and took them to Bobby and confronted him about them.
Matt -- While hanging out with Matt's Dad's girlfriend, she just happened to see pics of Matt with another girl, B. THEN, 2 people she didn't even know approached her and took a vote to tell her Matt was cheating on her. She called in sick to work, drove to another state to confront Matt and this Bianca girl -- Matt wasn't there, but "Steve" found it necessary to go warn Bianca. She confronted her at her home and talked to her for an hour and a half.
Travis -- she kept hitting back button on his computer until she ended up in his email account. She then proceeded to read every email between him and a female. Saw that he was flirting with girls about making out and was having "affair" with married LDS woman.
She snooped through his text messages when he was napping.
She logged on to his Facebook and Gmail accounts way after they were broken up and after she had moved back to California. She explained that Travis had given her the passwords to "re-establish trust" months after they had broken up. This is not believable.
She listened to Travis' voicemails 4 hours after she murdered him.
2. She moved in with every boy she dated.
3. Every time she got pissed, she packed up and moved, usually to another city. She was pissed at her parents for grounding her, so she quit school and moved in with a vampire and his elderly hoarder parents/grandparents. She was pissed at Bobby so she moved out and went back to visit Victor. She was pissed at Matt so she moved again to another city to get away from him.
4. Every time she broke up with a boy, she got back together with him and continued to have sex with him -- sometimes moved back in with him, and continued hanging out with his friends and family.
5. Every time she got a new boyfriend, she got a new religion
6. All of the "cheating", which led to the snooping and confrontations seems to have taken place after Jodi and her boyfriend-du-jour had already broken up. She just didn't seem to accept the breakup and continued to expect the ex boyfriends to be "faithful" even after the relationship ended.
So you put all this in context, and if I were on that jury, I would think the last visit to Travis was not something Travis knew about or invited. Based on her pattern with other boyfriends, as a jury member, I would believe that she went to confront Travis because she was pissed. I would think about how she behaved with other boyfriends and consider that she took a gun and knife with her this time -- and it would be pretty clear that she was so pissed that she drove several hundred miles to confront Travis and kill him.