It's worth noting that there's a distinction to make between formal and material heresy. Essentially it means that a person says or does something heretical but they lack complete knowledge or understanding that it is, indeed, heresy. Now I realize that seems like a silly concept with the Pope because, well, he's the Pope. He ought to have the best knowledge of the Magisterium out of all the bishops, right? I'm not sure that's always the case. It's a known fact not all Popes have been theologians, some of them have just had different charisms - and Pope Francis charism has clearly been more focused on social issues.
To become a formal heretic one would need to propose a heretical concept deliberately while entirely knowing it's heretical. This is where that safeguard comes in because if Pope Francis ceremoniously sat in the Chair of Saint Peter tomorrow and declared that Jesus wasn't actually divine, well that's a formal heresy and he would in that very same moment cease to be Pope. It's like a forfeiture mechanism understood to essentially be built into the office of the Papacy.
Some Catholics accuse Pope Francis of heresy, but I think even for them it's very difficult to prove formal heresy because he's never tried to codify anything or make an infallible declaration (really almost no Pope has, at least not since V1).
If I haven't answered your question, I would close by saying that really the best remedy is for Catholics to understand what the Church actually teaches and believes. To be well guarded against heresy one ought to have formed their intellect with the teachings of the Church through the catechism (preferably the Roman Catechism AKA the Catechism of the Council of Trent). Then if a Pope were to commit material heresy everyday laymen wouldn't be as badly scandalized and if he were to commit formal heresy they could take comfort in knowing he essentially removed himself from the Papacy in doing so.