I have had a few leaks around my Kubi gloves -- all user error. One time the O-ring was way over-lubed and the glove popped slightly out of the ring. Another time, I had left the rubber gloves in the sun for a month or so, and a little crack developed along a crease that I didn't notice in time. Lessons learned.
In both cases, the leaks were slow enough and the water warm enough that they were annoying, but not life-threatening. In both cases, I considered thumbing it, and instead continued the dive as planned, and just ended up doing 1 dive that day. The water here is +/- 10C / 50F. If you had to sit there for an hour of mandatory deco, or if the water was closer to freezing, I could see it being a problem. For my no-deco dives, just a nuisance.
I busted the wrist seal on one of my first dives in the suit, and just dove without wrist seals for a couple years. Both of the leaks I describe above had no wrist seal. Recently I replaced all the O-rings, and decided to put new wrist seals on for the heck of it. I find them to be annoying, and a solution to a problem I don't actually have, so I think I'll trim them back to being useless again. If I ever dive in way colder water, or start doing deco dives, I'll reconsider.
Tip: if you are trimming silicone wrist seals, don't use EMT shears! They will make a ragged cut that is prone to tearing. A razor blade or sharp scissors is much better.