Hello, I'm a very happy customer of over a year but have been bitten by the following scenario on both phones that I've used on Ting:
Receive new phone in the mail. Woohoo!
Activate phone via Ting.
Make sure phone works, do a test phone call, sign into Google, etc.
While you're busy with #3, the phone has been busy downloading new firmware in the background over Sprint's data network! Egads!
The first time I happened with my Epic 4G Touch, the phone was relatively new. I think it downloaded about 70MB or so, but my memory is not great. Not enough to bump up my bill significantly, but didn't leave me much overhead until I spilled over in to the next bucket. I called up Ting support and they graciously waived it. Since then, my carrier data usage has been under 100MB per month because I'm on wifi almost everywhere I go.
The most recent incident was a week or two ago when I activated a used Galaxy Nexus (BYOD). I pulled down around 180MB in data before I was able to connect to wifi! I haven't had a chance to call Ting's tech support and throw myself at their mercy, but if I forget (or fail), my bill for this month will have nearly doubled for something that's (to a degree) outside of my control. (I ended up flashing the phone to CyanogenMod at any rate, so I don't even reap the benefits of those now-superfluous megabytes.)
My proposal is this: after a new device is activated, allow for a window of 20 minutes or so where carrier network data consumed by the phone isn't counted towards the Ting bill. I fully admit that I don't know how feasible this is from either a business or technical perspective. The best solution would be to not count firmware upgrades in the data plan at all, but I'm sure that's not even remotely possible if the firmware data comes from random hosts on the Internet.
The least-effort solution: At the start of the activation, remind the user that if they have a new phone, any firmware updates are likely to be pulled down via the data plan and that they should connect to a wifi access point (or disable mobile data) **before activation **if they wish to avoid the related data charges.