Yep, graphic and industrial designers get worked over by stuff like this all the time. A big company puts out a "design competition" and hundreds of students, amateurs, and people early in their careers submit work. Often, by submitting you're giving away any intellectual property. A $5,000-$50,000 competition will net the winner a little cash, the company a new logo or product idea or large amount of material to brainstorm with, some advertising and some goodwill with designers... and the non-winning designers get nothing.

Anyone who's been in the industry for a bit will stay clear. There are tons of people in the industry calling for the end of this practice as it devalues the industry (quality of work and the compensation).