1) Unable to make phone calls because your phone is playing shenanigans with the network
2) Battery life is shortened because the phone is scanning for a data network
3) Watch you monthly billing statement closely for erroneous monthly data charges
Also, more retailers are starting to offer free Wi-Fi as Starbucks said they will be offering free wireless access to all customers with no registration, debit cards, time restrictions or other shenanigans. This is a great trend that will be expanding a lot in the coming years. We think data and voice will eventually be free because advertising will eventually be subsidizing these costs.