Am I consuming "roaming" services? I've borrowed an Android phone so I can decide whether to buy one. I have a GSM SIM without a data plan, but I am using Wifi that is broadcast from my other smartphone which does have a data plan.

The phone's GSM signal icon has a tiny "R" that indicates that I am roaming -- why?

My phone is an HTC Desire Z with (I think!) Android 2.3. 
Under Settings &gt; Mobile Networks I have these settings:
Data enabled = unticked
International data roaming = unticked
National data roaming = unticked
Use only 2G networks = ticked

The notification list sometimes shows me a message that is too long to be displayed, but some googling tells me that this is the complete text:


  "You have lost data connectivity because you left your home network with data roaming turned off"


The notification list also shows that I am in fact on the correct network: My SIM card is from the provider "bob" and the phone shows that I am on the "bob" network.

Am I consuming anything related to roaming? How can I ensure that I will not use roaming?
Maybe this post from XDA will answer your question.


  This isn't an APN problem, it is a SIM problem.
  
  Your provider has one set of numbers on your card, and another set of
  numbers that actually identify the network, and they don't match.
  Technically, from the phone's point of view, you are roaming, even
  if it is the same provider. From the provider's point of view, you
  aren't roaming.
  
  Up until cupcake, we had that same problem here in Canada when using
  the "Fido" network (which is owned and operated by "Rogers"). The
  network identified itself as "Rogers", the SIM cards identify
  themselves as "Fido", the phone think's its roaming.
  
  So; you don't need to worry about roaming charges when you are
  actually connected to the correct network.
  
  BUT; You don't have an easy to read display to tell you when you are
  really roaming, nor can you make configurations that are based on whether you are or are not roaming.