IAP without inbound course?

There is only one such IAP in the country (probably the world). If,
however, you mean most pilots don't know how to fly DME ARC initial
approach segments, then their training is seriously lacking.

They used to have several DME ARC final approaches in Germany. The
military especially used them as backup procedures to get to the airport
if the base facilities were off the air, and sometimes as primary
procedures if there weren't any on-field facilities. Most of the time
the arc didn't line you up with the runway centerline unless the
facility just happened to be perfectly abeam the airport.

John