The pink name identifies someone who's been given a second chance at the site as a whole. It has nothing to do with the lounge. Members who were trouble in certain areas and are brought back in pink in most cases have access to that area of the site removed. It is case by case though as each case is different. Members who have had access to the lounge or other areas removed cannot be identified via color or usergroup etc.. it's just gone. Hope that helps answer your question.
^ I brought this to Li's attention a while ago and agree with you, names for vendors, mods, probies etc... should have their colors displayed as they are on the main site. I also asked for the icon for threads you have posted in to be on the app as well. A lot of time and funding is being tied up in the legal issues right now though so I doubt those changes will be made in the very near future.