Actually, in the main DEN security lines, it's exactly opposite of this (or was as of Monday).

The signs @ DEN security state:

...
United: Premier Executive, 1K, Global Services, PassPlus (I think)
...
Star Alliance: Silver, Gold

It has always specifically excluded 2P from the United list, although plenty of 2P's have been able to use it and could probably argue the *S thing with TSA. It's likely the biggest benefit of being 1P in DEN, IMO.

Also, I haven't been there in a few months, and as a 1P never really paid attention, but I believe the Concourse A security line in the walkway does allow (specifically) 2P's. My wife is 2P and if the main line is long, takes the concourse A walk and can always use the faster line.