There are certainly security concerns for celebs in the park, but they depend on who those celebs are and their level of recognition.
I've seen James Corden and his family quietly escorted through the back exit for Midway Mania. No muss, no fuss, but still the special treatment. I was honestly the only one around who even noticed him, but it's because I recognized his voice immediately as he passed by.
I've seen Maya Rudolph just wandering with her family with no one paying attention. I don't think she even had a plaid.
I've seen John Legend and his family with security, which raises their profile, but while people looked, I didn't see anyone approach.
Here's the treatment they got recently for a special occasion - including their own boat (and Disneyland photographer to record it for PR) on Small World:
Chrissy Teigen and John Legend's daughter Luna celebrated her birthday at Disneyland while wearing a costume resembling that of Jasmin's from Aladdin
people.com
And I've also seen hordes of screaming women shouting after Kobe Bryant when he was in the park one night with his family and a whole crowd of Disney security was desperately trying to run them backstage to keep them safe.
I'm not saying the Kardashians are Kobe-level. But the attention and therefore security risk they draw may be.
Was it tacky & obnoxious especially considering they all go to the parks often rather than once in a lifetime? Sure. It's the Kardashians. Does it suck when you're the guest waiting to ride? Absolutely. Are the Kardashians now Disney celebs with extra privileges beyond what they always paid for when they regularly visited the parks? Also, yes.
But as someone who Kobe & family had to rush past to escape screaming fans literally chasing after him, I've seen how scary it can get with celebs at the park. Which is why ones that recognizable get an extra security perimeter. And others don't. It can turn ugly faster than you'd believe.
With that said, do I think they're going to pull that again and get away with it? Nope. Think this one got enough bad publicity that they'll simply bring more people next time and fill the vehicles with their own people so it doesn't look bad but they'll still have their perimeter/special treatment without looking like such divas. Or not.