This is merely conveying the true statement that the ER cannot and does not act the same in the "real world" as it does in residency.
This is local/regional. I trained at a place with high-powered IM and surgery, and I had attendings that would let me and my colleagues swing in the wind, when we weren't sure or needed guidance (hell, I had an attending sandbag me for a patient that just needed phone consent for comfort care - he convinced the family to go for full code except defibrillation - first and goal at the 1, and we get a field goal), while having an über-brainy come up with reasons to not admit a patient (at least to their service) (one gorgeous but nasty woman was especially adept at "this patient isn't right for internal medicine" - as a colleague said, "If they're not going directly to the OR, they're right for IM!"). One ***hole that had done the trauma fellowship at ShockTrauma many times (i.e., more than 3) take procedures away from residents first-off (that is, not let a resident try first). However, my program director was hands-on plus - she would not let us cut corners, and seemed to be there at every moment when one screwed up. If/when she heard someone on the phone with a consultant (or heard peer-to-peer from the attendings) that didn't know data they should, she was correcting them.
Residents are an available resource. My first job out, I had surgery residents, but no EM program. One guy was a total douche, and the attending beat him to the patient bedside (and the attending wasn't running) to put in a chest tube for hemo/pneumothorax. This resident was always "no, no, no", and was wrong more than once (he was a senior - PGY4 - that had transferred to this program), despite his stridence. I don't know what happened to him, but we predicted a difficult path for him in practice. However, most of the surgery residents were good, and, if they were MFing me, they did a REAL good job of hiding it. Despite me saying "I can **** on a resident", I only called emergently once when I had an old lady that fell and had a scalp lac that was gushing and I couldn't stop. No flak from the senior - he came down, and did a bang-up job closing it. I didn't call surgery for my lacs, except to ask if there was a student that wanted to sew. I did, once, in fast track, call for an abscess in the groin on a female, because I didn't want to mutilate her genitalia (it was groin, but low, but not in the vag and not a Bartholin's). The surgeons took care of it, and the attending (who is one of those old, grizzled, 60-some year old guy still taking Q4 call, and wears a bow tie when he's in the office) would needle and rib me about it, asking if I had any abscesses for him, but, if that's what it took - me having the **** taken out of me, and me not turning this lady's gear into a hacked mess - then I'll take it every time.
Sum total - some residents learn it earlier, some learn it later - and some don't learn it until they're attendings.