It is perfectly alright to not have your LinkedIn profile updated. Most of my batchmates didn't have one when they were interviewing. No partner/ principal has time to go through the LinkedIn profiles of candidates. It is usually someone from the organizing team as Benjamin correctly pointed out or at worst a junior consultant.
Having said that, I would suggest you update your profile as it is slowly becoming the starting point for recruiters and companies to get a quick scan of their candidates. But trust me, it doesn't change anything. Please attend the event as you would have otherwise and make a strong impression. All the best to you!!