You’d be surprised how many people are convinced they have had visions from God.
I wouldn’t be surprised at all to be honest. One look at the Internet shows that there are people claiming they have visions from God on a regular basis. Why would you think it is such a surprising thing?
Many of us here believe that saints speak to us from time to time, or even God speaks to us. However, those of us who are firm in our faith simply discern/ accept the message and move on.
Also, the OP’s post was not about God simply speaking to people. It was specifically about “visions” and “ecstasies”. Most people, even those who feel they hear from God or a saint regularly, do not go into ecstasy, nor do they have a vision. They simply realize or feel on some level that God or one of his saints is speaking to them. Visions and ecstasies are very specific, unusual manifestations of God that do not happen very often or to most people.
The OP indicates he is concerned about other people’s visions or ecstasies. The only time these would be of concern would be if the person is claiming to convey a message to the general public through their visions, or if the person is a friend or loved one of the OP.
If it’s a friend or loved one of the OP claiming to have visions, they should be put in touch with a priest and if the situation seems to call for it, a mental health counselor.
If it’s just some stranger claiming to have had a vision, then the OP should look at all the circumstances surrounding it, such as if the person is Catholic, if the Church looks favorably on them/ their vision (like is the vision an approved apparition, was the person canonized as a saint, are Church officials investigating their vision etc), are they saying anything contrary to Church teaching, are they soliciting funds (often this is a red flag). Generally it is best for Catholics to not be too concerned with the purported visions or ecstasies of other people unless and until the Church has approved the vision or canonized the person, or at least put him or her on the path to canonization.
I pretty much ignore anyone making claims of visions or ecstasies unless the Church promotes or approves them in some way. I do not have anyone in my close family or friends making these claims; if I did, and it was happening more than as a one-time thing, I would want to gather more information from priests and medical professionals to see what was going on with the person, as such manifestations could be symptoms of a mental illness.