I think the discusion is missing a basic point. Why does PE certification exist to begin with? Does a reasonable standard or industrial accepted practice have any bearing? Did the owner suffer any damage, comparable with liquidated damages, or suffer unneccessary high risk due to an error or ommission that conflicts with code or standard practices?
I have been involved as owner's agent on multiple E&O's, and have worked arrangements with bonding agents on multiple occassions after termination of the A-E for E&O. Largest one has been 8 figures, mostly just in the seven figure range.
As an example, working in wet laboratories, a nationally recognized A-E in BSL and lab design decided to ignore NFPA 45. Such ignorance led to exhaust duct being split for 3 floors, and potential exposure of dozens of lab personnel, as well as myself, to dangerous, toxic airborne analytes. The A-E claimed no E&O as they were compliant with NFPA 90A. The decision went to the IMC, which required field interpretation to include mandatory compliance with NFPA 45 and subducting. If you are an ME and work in lab design, you may have sen the IMC subducting field interpretation. That was E&O bot nothing like the E&O that came from their previosuly having the same interpretation on 8 to 9 figure screw-ups on national laboratories in Atlanta and Bethesda. This was definitely an error and not an omssion, very clear cut, with owner warning the PE beforehand that this would be considered an error, and appealed to the IMC. Had to go to the IMC as the Federal governent, in the form of the COE, supported the erroneous position of the PE in question. Egg fart in somebody's face.
Having the owner go at risk, and being cited by OSHA for violations borne from a PE licensed design, is another 7 figure example I could mention. If the PE design leads to the owner receiving a NOV from OSHA, I believe you have a good starting point for an E&O. I've experienced that twice in the state of Maryland. As a result of E&O, literally hundreds of cusomters were exposed to extremely high levels of airborne copper.
Toughest one I had to deal with was a design build for renovation of an ABSL-3 lab, directly adjacent to a hot agent BSL-3 laden with anthrax. The construction agent mistakenly cut through exhaust duct from the hot BSC; fortunately, the barometric "dumper damper" in the mechancial room kept the lab from going positive. The construction arm (who was also the GC) stated that they were only following the design hence were not at fault, a risk previously mitigated by the owner. A post award modification, not approved by owner, had the PE issue a change order to cut the exhuast. As the contract was with the GC, the GC owned the error of the PE, paid out 7 figures, was terminated for default, and the bonding agent selected a new design agent (which turned out to be a tremdnous conflict of interest, but worked out well).
If there were not so may bad PE's, and PE's with egos greater than their IQ, E&O would not be such an issue. Errors are a lot easier to identify and punish than omissions. I've never done a 7 figure omission claim, but have recommended on multiple occassions that the cost be equitably shared between owner and A-E, as owner would have need to pay for the omssion to begin with.