Not the risk that its being made out to be
With SMS there's a FROM and a REPLY TO field. The issue was supposed to be that you could spoof the REPLY TO fields and users would end up sending to a premium number without realising it. The iPhone shows ONLY the REPLY TO number so that won't happen.
The SMS standard allows to to spoof either sender field, so you're no more secure if you see the FROM number, and a number of bulk SMS systems will show you their internal ID, not the correct ID of the system to contact so that it isn't work using that field instead.
Conclusion: SMS isn't secure and isn't likely ever to be. Treat with caution.