From the media guys scared to death of losing access, absolutely they shouldn't be trusted for accuracy about trade and contract rumors. The agents and front offices feed them info to put out, there aren't alot of legitimate leaks since that's a career killer for staff. This isn't new, most sports franchises have been fairly media savvy since ESPN put on the Ocho.
If it's from the gm's mouth or an official mouthpiece for an org, I think it's fair to say it's accurate. If it's something about a "maybe" trade or anything that could pump the market value on a player, hell no.