At my dojo we apologize if anything like that happens, but our sensei and sempai say it is their job to be aware and stay out of our way (though I feel it is my job not to run into them or send my uke rolling into them as well)
Hah! Just yesterday we were practicing and I landed near, but not dangerously near, sensei. We made a joke about "bowling for sensei".
He took a few steps away.
We were just kidding. Mostly. :-/