I don’t mind high CR random encounters. Keeps me on my toes as a GM, and encourages improvisation.Under most circumstances I'd agree, but since we're talking about a random encounter that (if I remember the Martek portion correctly) just pops out of the ground/glass and starts snacking, it should probably be modded in some fashion to avoid a no-win kill-a-character-or-three moment. Now, if it's modded as a "cutscene instance" like [MENTION=40552]Quartz[/MENTION] describes, where only major stupidity would get them killed, that's not too bad, and gives them the idea of the danger level if caution is not observed.
Speaking to my own DMing style, I don't like to set up encounters where my players have to use all their resources to survive unless it's part of the main mission they're on. Because we have limited game time, any random encounter that 50/50 could be a TPK I avoid, because it would feel like a chump move, if a moment's tactical mistake or bad roll causes hours worth of reset while we either roll new characters or start a new campaign. I try to aim for more Firefly or Seven Samurai and less Walking Dead/Game of Thrones.
And it’s more open ended, rather than being a set encounter, which tend to be more obviously non-combat.