So if I transfer my unlimited line upgrade to a feature phone and get a subsidized smart phone with it and a $29.99 data package I can switch the phone to my unlimited line the next day, cancel the data package and downgrade back to a feature phone to keep unlimited? Seems pretty easy. If this is true, I'll go try tomorrow.
Search for my other thread on this to read the experiences of those who have done it. Others have done the following and kept their unlimited:
1) Transfer the upgrade from your unlimited line to a line on your family account that does not have unlimited data (either capped data or no data at all);
2) Buy a subsidized smartphone using the transferred upgrade;
3) Activate the newly purchased subsidized smartphone on the non-unlimited data line - you will have to pick a data plan at this point if the non-unlimited data line did not have a data plan on it - pick 2GB for $30;
4) Reactivate the phone that was originally on the non-unlimited data line on the non-unlimited data line - the data plan will automatically be removed if the original phone was a dumbphone; and
5) Reactivate the newly purchased subsidized smartphone on your unlimited data line.
The hitch in all of this is that your unlimited data line contract will be renewed for 2 years, which you may or may not want.