I see two possible outcomes of this business model:
1. The gov't catches wind, demands you keep proper records and you say "no" so they shut you down.
2. The gov't comes to you asking for identifying information for a customer, you say "no" and they shut you down.
I honestly don't know that much about it, so I can't claim that these two are the only possible outcomes.
Can you provide more details? What are the regulations? Do you have a plan if the gov't comes knocking?
But we have to take your word for that, right? How do we know you're not a front for an NSA sting operation? (Feel free to treat that as a rhetorical question :-)
What are the regulations?
If the gov't wants to track down the owner of a phone, what do you do? Just say that you don't have that information?