Its such an odd thing many traditional priests encourage people not to attend "other" traditional masses than their own, and even encourage the laity to avoid mass altogether.  The trouble is, that for the ailment of modernism, indeed for all spiritual ailments, the remedy is Jesus Christ.  Not just in spirit, as in praying at home alone, but in fact, in communion, at the mass.  We are told however, that there were times in the past when Catholics didn't go to mass because the priests compromised, assuring us the priests in question were heretics and the people turned their back on them.  That well may be, but there is no proof that not going to mass of a compromising priest was even the proper answer.   Even if people chose not to attend a compromised mass being forced out by sacrilege, for instance, unless and until such a thing occurs, leaving mass is not wise and may even be disastrous.  Obviously, its not ok to compromise, the thought is odious. However, the mass is protected from the priest that does evil.  Some say this does not extend to the priest who has become an heretic or for sacrilege.  But the truth is, that unless the Church deposes him, we are forbidden to remove ourselves from the mass and our hierarchical authority. Canon law says: 1.The censure of excommunication is incurred automatically by one who knowingly commits any offense that carries the penalty (such as internally denying a dogma within his heart). Such excommunications can be public or occult (secret) (48), and require no warning or declaration, per se. However, when the public good demands it, a declaration must be issued for a person to be considered to have incurred the excommunication in the external forum. (49) And, as the canonists teach, when the person in question is a cleric, the public good does demand it. (50) Therefore, while a cleric may have secretly incurred excommunication in the internal forum, he is not considered to have incurred the censure of excommunication in the external forum, without a declaration by the Church.But what is important to note is that the censure of excommunication does not result in the loss of office for a cleric. The loss of office is a vindictive penalty, and vindictive penalties always require a warning (usually two). (51) In fact, as mentioned above, even in the case of a more severe vindictive penalty, which is incurred by a cleric who publicly defects from the faith (canon 188.4) by joining a false religion, either formally (sectae acatholicae nomen dare) or informally (publice adhaerere), a canonical warning is required before the office is rendered vacant. (52) 

And also, 2.“As divine scripture clearly proclaims, ‘Do not find fault before you investigate, and understand first and then find fault’. And does our law judge a person without first giving him a hearing and learning what he does? Consequently this holy and UNIVERSAL SYNOD justly and fittingly declares and lays down that no lay person or monk or cleric should separate himself from communion with his own patriarch before a careful inquiry and judgment in synod, even if he alleges that he knows of some crime perpetrated by his patriarch, and he must not refuse to include his patriarch's name during the divine mysteries or offices. (…) If anyone shall be found defying this holy synod, he is to be debarred from all priestly functions and status if he is a bishop or cleric; if a monk or lay person, he must be excluded from all communion and meetings of the church [i.e. excommunicated] until he is converted by repentance and reconciled”. Fourth Council of Constantinople

It is a concern that the infection of modernism is so deadly, it isn't worth the risk of mixing with those who have imbibed it.  While this is true to a great degree, it isn't true to the point of missing mass.  For instance, we do not cease to interact with the rest of the world because it's heretical and apostate, why do we do it when the stakes are higher and the loss far greater? Modernism is highly contagious and extremely deadly, we know.  But the remedy for the worst case modernism is readily available at the mass and the remedy is Jesus Christ!  To suggest mass is too dangerous, is to say the heresy is greater and more powerful than the remedy, which is Christ.  Doesn't the Church teach that where sin abounds, grace abounds even more?  Why are our priests steering people away from the mass?  Aren't the laity tired of the fracturing, dissolution and destruction of the Faith by modernists?  Why do they tolerate further division from their own priests?

This is old.  Priest with no valid Holy Orders, have nothing, give nothing, people get nothing.  The Mass is not Mass in the New Order, just a show. This being said, those who go to these events are putting themselves into occasions of evils errors, blasphemy and etc.

Chapter 12 of Daniel, referred to by Christ to his apostles states that the "continual sacrifice" will come to an end.