Events can be a great place to make connections and it hints that the prospect is in a mindset of being willing to open up. Assuming of course what you are selling fits the theme of the event.
You can use phhantombuster for this which has a free tier. You'll get 10 minutes each day and each task(scrape a profile in this case) roughly takes 30 seconds. Not a lot, but good enough if you want to test the waters.
1. Signup for Phantombuster and browse Phantoms in the homepage
2. Use this Phantom
3. Connect to LinkedIn and save
4. Paste the linkedin event link
You have to attend the event before this step!