Beckett holders are impossible to break without pretty much destroying the slab from future use. So scammers are now selling cards in counterfeit Beckett holders, that even Beckett sometimes can't tell apart.
https://www.blowoutforums.com/showthread.php?t=1435178
SGC were easy to take apart and reseal, and older PSA holders were as well. The current PSA "lighthouse flip" holders are more like BGS and should shatter/crack upon opening rather than just get frosted on the sides. So if you're worried about your cards slabbed before 2019, now may be the time to send the higher valued ones (or the partially frosted ones) in for Reholder.
Add: But if you haven't been following the altering/trimming scandal, this #57 Michael Jordan '86 Fleer has been trimmed a considerable amount of times, and received number grades from all the major graders. The Robert Block thread in the Blowout member feedback section is worth reading.