No, for the most part, the shrimp are smart enough to get out of their way. But the plecos don't really move around all that much either, I think the only time I see the two interact is when there are wafers or pellets on the bottom. And usually the water current that the plecos churn up is enough to push the shrimp out of the way when they are rummaging.
Every once in a while I see the shrimp crawling on the plecos also.