In reality, one cannot absolutely refute the possibility of seeing Imam during occultation. There are testimonies to the truthfulness and correctness of this matter in many instances. Renowned and trustworthy figures like Abraham Mahziyar, Allamah Hilli, Sayyed-ibn-Tavoos, Allamah Bahr’ul-Uloom, Majlisi, and several others have indeed visited Imam Mahdi. However, they never spread news of their meetings in the society, and would divulge only to a few of their close followers. Besides, they would take an undertaking from their intimate friends not to disclose the matter to anyone during their lifetime and if they wanted and if need arose, they could reveal it after their death and that too only for the sake of finalizing the argument.
However, these are exceptional cases that were divulged by the fortunate ones and resulted in ethical and spiritual benefits.
It’s worthy to mention that it was the custom of great religious figures not to misuse religious privileges for achieving worldly gains or consider them as a means for promoting their material life.
During our times, it has been heard that a few unknown characters have gathered around themselves certain people (particularly illiterate ladies) by the claim that they have direct relation with Imam (a.t.f.s.). They narrate unreliable and unauthentic matters by means of which they brighten up their gatherings and reap material benefits. However, they never involve themselves in discussions and reasoning and close the way of wise people for any type of research and investigation. Also, certain writers exhibit such meetings with Hazrat Mahdi (a.t.f.s.) to be so easy, low and insignificant that perhaps Hazrat is anxiously waiting to show himself or present some gift to any rouge in exchange for his two unit prayers or one line Ziarat.
We have ourselves seen great personalities who have spent most of their blessed life in propagating the Ahl al-bayt creed and promoting Hazrat Mahdi’s name. But they never referred to the matter about visiting Imam (a.t.f.s.). Instead, they encouraged their friends and near ones to recognize and serve their Imam (a.t.f.s.). One witness that brings to light the custom followed by great scholars in their meeting with Imam (a.t.f.s.) is a memento that Sayyed Mahdi Tabatabai Bah’rul-Uloom has experienced with Mirza Qomi.
Mullah Zain-ul-Abedin Salmasi (student of Bah’rul-Uloom) narrates:
After visiting the House of Allah and the graves of Imams (a.s.) in Iraq, Mirza Qomi attended Sayyed Bah’rul-Uloom’s class. When all the students left the class, he requested Sayyed to donate a few of the innumerable bounties that he has acquired.
Without any hesitation, Sayyed said, “The night before or two nights before (doubt from narrator’s side), I visited the Kufa mosque for performing the supererogatory prayer. I intended to return to Najaf at dawn. I left the mosque very eager to visit the Sahlah mosque. However, I changed my mind from going because I feared my class would close down. On the other hand, my eagerness grew more than before. In such state of uncertainty, a strong wind blew and dust rose in the air. I was driven in that direction. Moments later, I found myself near the door of Sahlah mosque. I entered the mosque and found nobody save a noble man engaged in invocation. His words made one’s heart calm and eyes tearful. My state transformed and my heart took off. Tears rolled down. I had never heard such words before. I realized that the one reciting himself composes and wasn’t reciting out of memory.
I stopped and listened to him. I was extremely delighted. He finished his invocation. He turned towards me and said, “Come Mahdi”. I went few steps forwards and then stopped. He ordered me to still come forward. Once again, I went a few steps ahead and then stopped. He again asked me to come forward and added,“To obey is good manners” . Moments later, I went forward until my hands could reach him. Thereafter, he uttered some words.
Here, Mullah Zain-ul-Abedeen Salmasi says:
When the talk reached this stage, Sayyed refrained to continue and instead started to reply a query that Mirza had inquired before. However, Mirza asked him what words that man had uttered and Sayyed replied,“It is from the concealed secrets.” 
Such is the custom of our scholars in safeguarding the secret of meeting. They disclose to the people only to the extent of finalizing the argument before them.
We see how often noble men, scholars and the elect see Hazrat Mahdi (a.t.f.s.) but divulge this news with great difficulty to others. Of course, their melting state itself reveals that they have been among the fortunate ones. But they have acted in such manner that others are prevented from taking any undue advantage or any illusion or suspicion is done away with.