I disagree, 'EXECUTIVE". A qualified tire technician will know where and what to look for with the tire inflated and jacked up so a 360 degree check can be made. Mostly you are looking for cuts or belt separations. Cuts are obvious, belt separations will begin showing up in the tread grooves nearest the shoulders.
I suppose in a very, very minor number of cases you may discover a problem inside, but in my many years I found most cases signs of problems with radials will transfer and make itself known on the outside, again if you know what you are really looking for..
'40 years in the tire industry; seen it all and done most of it"