When text message has been blocked, the sender receives the following return error text on phone: "From 9230, the recipient you are sending to has chosen not to receive messages from this sending address. Msg 2108."
How recent is this information? I tested a blocked user and they have not received a reply message. Is this information still valid, or does it block them, but they don't receive a response?
The last time the internal article with this information was updated was 11/3/10 but I have not tried this myself. Let me see if I can get a hold of one of the Messaging Product Managers to confirm. Maybe things have changed.
When you have a number blocked and they text you, they should get that error message and you obviously won't get their SMS.
Having received a messaged from Honduras you have the number that it came from if there was a public list of numbers you could do a reverse lookup. There is not publicly available directory of cell phones numbers for Honduras that I could find. Which is the only way that I know of that you could trace the number.