I have since accepted a great full time position related to my field of studies that I love since asking this question. Thinking back, before I decided to work with this company, I did some research online about them and from what I found out, the company was local (US based), with a operating history of > 10 years and specializes in IT recruiting. Client ratings were satisfactory.
In the initial phone conversation, the recruiter asked questions such as my requested salary range, preferred job location, preferred industry, and details about related work on my resume. I appreciated the recruiter taking the time to find out about my needs in a job. The recruiter appeared competent and nothing stood out as troubling so I went forward with a face to face meeting. I was given the chance to ask questions regarding the above listed areas, answers to which I found acceptable.
I had an unfortunate experience as I detailed in my linked question. I eliminated any possibility about working with this company in the future. My goal would be learn about the red flags that I must have missed.
The particular recruiter I worked with was young, not more than 5 years removed from college, for which this event could be due to inexperience.
How can I evaluate the legitimacy of a outside recruiter if I decide to work with one in the future?