  We provide a simple $(1-O(\frac{1}{\sqrt{k}}))$-selectable Online Contention
Resolution Scheme for $k$-uniform matroids against a fixed-order adversary. If
$A_i$ and $G_i$ denote the set of selected elements and the set of realized
active elements among the first $i$ (respectively), our algorithm selects with
probability $1-\frac{1}{\sqrt{k}}$ any active element $i$ such that $|A_{i-1}|
+ 1 \leq (1-\frac{1}{\sqrt{k}})\cdot \mathbb{E}[|G_i|]+\sqrt{k}$. This implies
a $(1-O(\frac{1}{\sqrt{k}}))$ prophet inequality against fixed-order
adversaries for $k$-uniform matroids that is considerably simpler than previous
algorithms [Ala14, AKW14, JMZ22].
  We also prove that no OCRS can be $(1-\Omega(\sqrt{\frac{\log
k}{k}}))$-selectable for $k$-uniform matroids against an almighty adversary.
This guarantee is matched by the (known) simple greedy algorithm that accepts
every active element with probability $1-\Theta(\sqrt{\frac{\log k}{k}})$
[HKS07].
