Jim, there are no rules here regarding TM names, because there is a huge gray area. We would be getting involved with legal disputes, as there is no way for us to accurately know what is actively TradeMarked in many cases. Besides that, some people are okay with purchasing TM names. Some TM holders even encourage others to have their TM in domains if they are used in a positive light.
That being said, we should feel free to advise bidders (especially newbies) that there is a possible issue with buying a particular name whenever possible.