In most cases, the answer is no. Running a test with no think time unduly stresses out the grid nodes - it's almost as if you were testing the grid nodes rather than your application. To prevent this, add think time to your scripts. For JMeter, we recommend using a Gaussian Random Timer to space out your requests. This will more accurately simulate users interacting with your site, such as typing their details into a form, and then clicking a button that sends the request.