Pune society demanding notarised copy of purchase agreement

Q 1 Yes, it is required.

2. No. there is no risk, it is safe.

3. Academic and subjective topic for debate.

You are required to comply with the essential requirement/formalities in this regard, what is your problem to abide by the law?

You cannot agitate or object to the legal procedures.

Sir,

Could you please let me know the specific provision of the Maharashtra Cooperative Societies Act, Rules, or the Society’s registered Bye-laws that requires members to submit a notarised copy of the registered purchase agreement?

You can peruse the bylaws of MCS act and search for relevant provisions.

Did you do your homework / research work before giving an examination to experts on this platform who are from all over India and may or may not be from Maharashtra qua specific provision of MCS Act/Rule/Bye-Law of your society ?

Hello Sirs from where to do research ? Any link / article will be appreciated. 
meanwhile I talked to advocate yawar via online help . He said only a copy of purchase agreement should do and and notarised agreement is really not needed