@Ian *****
and while it is anecdotally interesting that you've not been asked for a TM.30 receipt, the fact you have a yellow book does NOT exempt you from needing to have filed a TM.30 form.
As you can see by even a rudimentary search of the inter-web, more and more immigration offices are asking for proof of having filed a TM.30 to get extensions, re-entry permits, file 90 day reports etc.