Best trick to know opinion without revealing the name in a group

I am attending a workshop named lean startup. 

As appears by the name, this workshop is to provide information about how to open a startup, specially what one has to consider before starting a startup.

There is enough materials related to concepts and methodology. 

Sometimes we tested the methodology with any idea of startup of the participants. 

How to work in a group and how to identify the factors which need special attention etc many such activities have been performed. 

One thing which comes in my attention is a trick which is applied to know opinions of participants on an issue without revealing their names. 

All participants are there in a group attending the workshop but no one know who has voted positively for a question made to solve the issue and who has voted negatively. 

An issue can be solved by answering several related questions. 

For example: You are a head of a team. 

Previously a worker of your team was performing the best but now this worker's performance is less than previous performance. 

You have talked with this worker several times on this issue. 

You and the worker know that the worker's contract will expire in 6 months and you don't know what can be done in this situation. 

You think you are very careful and continuously demanding the best performance because you consider that this is the only way to open a new opportunity for the worker. 

Who is responsible for the worker's performance? 

If it is not possible to renew the worker's contract after 6 months, who is the responsible? 

Keep in mind that this worker knows how to achieve the best. 

What do you think? 

You can write your opinion in comment section. 

The participants apply a trick in this case. 

As a first step all the participants together identify the questions which are necessary and must be asked to solve this issue. 

Then, all the participants of the group close their eyes except the participant who is the head of the team and who considers doing all well with the worker to solve the issue. 

No one can see the face of no one of the group after closing the eye. It is ensured well. 

Now, each question is asked to participants complementing that you agree or disagree. 

The participants can indicate their agree or disagree only by raising their hands. 

When the participants opened their eyes after answering all the questions, they saw full surprise on the face of the head of the team. 

The head never thought about the mistakes doing with worker. 

Also, the loss is not of the worker. 

It is a loss of the head of losing a best performer of the team. 

During the workshop it has been used several times by the workshop presenter and speakers to know the opinions of the participants without revealing the name of opinion givers. 

I think this is a good trick and can be easily applied to solve an issue. 

Inside the family also it can be applied to solve several conflicts. 

In the work place also, there are many conflicts when you are working in a group. 

This can be solved by organizing a team meeting and then everyone close the eyes at a same time and give answer of questions prepared for solving an issue. 

I think there should be a team of 2-3 persons in each workplace who can receive such type of in-puts from workers without knowing their names and they can put it in front of administration. 

May be you say human resource department has this role. 

But many time workers don't inform the issue which they are facing due to having afraid of losing the job. 

But closing the eye and knowing the opinions is a good trick to solve many issue.