If $G$ is a graph and $G-v$ is linkless for some vertex $v$, is $G$ necessarily knotless?
Of course, one can assume that $v$ is adjacent to every vertex in $G-v$.
Here, a graph is linkless if it has an embedding in 3-space with no two linked cycles. And a graph is knotless if it has an embedding in 3-space such that every cycle is an unknot.