Interviewing ruby on rails developers

I was with ruby on rails web development for past 4 yrs.In this 4 yrs i have attended several ruby on rails interviews.Out of 25, i can say just 5 of them have asked a better one.Till now most of companies have asked the question which was taken from the Google, some of the questions are

Whats the difference between dynamic scaffolding & Static scaffolding ?

Whats the difference between Symbol & String?

Whats the use of flash and session?

How we can access multiple database.?

How we can access ajax calls on controller?

Some times, if a interviewer is on diff tech background then he will ask the above questions definitely added he will be asking the questions from his own stream (Ex : JavaScript, Sql or any scenario questions). Once i attended a top mnc company, they just asked did you know how to work on rspec, internalization and whats the team size of your current project.The worse thing of another interview was, the interviewer prepared a set of questions on paper and he just asked one by one.

What is class, Object, Superclass?

Whats is the use of attr_accessible?

Whats the difference between has_many :through and HABTM

If our interviewer is a database developer, then the questions will be on database. And there seems to be no questions on Rails.Some times if the interviewer is having less yrs of exp than the candidate. Then he will fire out the questions as if he seems to be master behind the rails framework. Not but not least, one of my friend has taken an interview with a product based company,as the interviewer is from Java he has asked the questions, which seems to be like this

What do you mean by private variable

What is static methods

How many levels of inheritance is there on ruby

When Dave Thomas Meta programming screen casts becomes popular, all of a sudden asking on Meta programming. Among these interviews, some interviewers from MCCAFEE & AT&T will ask only about the project and the technologies we are using on it.
Finally, very small amount of companies are asking genuine questions to the candidate.Sending a scenario and asking then to do with design patterns.Also they won't worry about rails, they just go with ruby and test cases.

*Note

These are all my personal thoughts, if any of the context harms any one.We apologize for this.