We have a pretty good system at Stony Brook, basically a two tier system.
One is a 'trauma consult' for serious but nonemergent trauma, we get the senior surgery resident to see a patient after we've already worked them up. The consult can either be helpful (finds fractures that we missed) or painful (he's still got C-spine tenderness, get flex-ex. If those are negative and he's still tender, get an MRI). I don't like to get a trauma consult unless it means trauma admission.
The Code T: trauma alert brings down everyone in the hospital, including anesthesia and the trauma surgeons. We don't like to call a code T unless we're pretty sure that the patient has a serious traumatic injury. Unfortunately, Code T does not assume trauma team admission, which I find annoying. If it's bad enough to call a code T, trauma should take the patient.
The way we did it at Temple, calling a trauma alert meant automatic trauma admission. This made the ED run a lot smoother. Note it doesn't make that much more work for trauma: they still write a full H&P whether it's a consult or admission, and pretty much follow the patient the same way, consult vs admit. The only extra work was discharging the patient if they could go home, but this is probably less work than the arguements we have now about whether or not the patient needs to be admitted. I rotated on trauma only three months ago so I still remember how it works.
I'm of the opinion that I call specialists for two reasons
1) Admit for further workup
2) Procedure that I can't do myself
I don't like to call a consult just to get a second opinion. Either the patient is emergent and needs emergent help (scope from GI, cath from cards, OR for appy) or admission (r/o MI, NPO/IVF for SBO, etc), or the patient has a nonemergent problem that can be seen as an outpatient (nondisplaced fracture, chronic HTN, etc)
On the flip side, when I'm ready to admit, I'm ready. None of this 'let's call another service and see if they want it'. They don't, or I'd have already admitted to them.