Meh, not really that uncommon because many of the IPM manufacturers changed to adding better fly-back diodes in the package so the transistors don't see the same di/dt. That took place maybe 10 years ago. The problem is that not ALL VFDs are going to have that, so you can't GENERICALLY say its OK to not have the aux contacts, plus most drive mfrs stop using the IPMs at around 50HP, reverting back to discrete power transistors again. So whether or not the beefier fly-back diodes are there becomes a function of the quality of the design and as we know, not all drives are created equal. So it's likely that ABB has made a decision to always put the beefier diodes in, and more power to them, but they are not unique in that.
But like you, I'd worry about this on larger drives in particular anyway. A few hits from disconnecting under load and those diodes short, then the next one takes out the transistors. So the beefier diodes basically just buy you some added fudge factor, but it's still not something I'd bet the cost of a 100HP drive on, especially when the REAL cure is to simply add some $10 aux contacts.