AXPONA 2017 Protocol

I need some wisdom from this community. I'm attending AXPONA for the first time on Saturday, April 22. I specifically want to hear a selection of certain speakers in order to narrow down what I plan on auditioning in my home. So, is it encouraged or frowned upon to bring a USB with various musical selections on it and ask for the USB to play through the systems being demonstrated? Also do any serious price negotiations occur at AXPONA, or is that expected to happen at a later time in a more private setting? Finally, I would appreciate hearing from veteran attenders the absolute one thing I must experience on my one and only day and also the one thing I should not waste my time with at the show.
I look forward to your insights and advice.