Hello @sls2!
I'm sorry about the delay and I hope this message isn't to late! I'm not sure if the Square Point of Sale App will run on 2G. I tried limiting the data speed on my personal phone and the lowest I could get it to go is 3G.
If WiFi is avalible at the event I recommend utilizing it. If not, you should take a look at Processing Payments in Offline Mode. This can be accessed from the settings page of your Point of Sale App. Please note that there is some associated risk with taking payments in Offline Mode. If a card is declined you won't be notified until the payments are uploaded. Writing down the buyers contact information on paper is a great back up if you plan on using this feature. That way you can always contact them if need be.
I wish you the best of luck at your event! 😀
