I do see this in their TOS ,
"Resource Usage
User may not:
Use 25% or more of system resources for longer than 90 seconds. There are numerous activities that could cause such problems; these include: CGI scripts, FTP, PHP, HTTP, etc.
AND
While our shared services are suitable for the bulk of our customers, there comes a time for some websites when they are better suited for a larger plan, which allows for more dedicated CPU and memory resources. We reserve the right, in our sole discretion, to discontinue service to any customer with a website or other hosted data that takes up more than 10% of the server resources and/or 10% of the server's CPU. This means that if your website is found to be utilizing more than 10% of the CPU and memory of the service, we reserve the right to take your site offline. If this becomes necessary, you can either upgrade your hosting package, or request a pro-rated refund of the amounts you have paid in advance for the services. Due to the severity of this, and our ability to act quickly to correct these situations to avoid server issues, we will do everything reasonably feasible to provide you with a warning prior to taking your site offline, but we accept no obligation to do so."
depending on how oversold the server your on is you could be in violation of the resource usage policy fairly easily. The last host i worked with kept all servers at 93% capacity at all times, so a couple of fairly small wordpress blogs with very little traffic would cause CPU timeouts. Our inside Joke was that our servers were only good for parents to upload pictures of their kids. Little trick for you, If your host gives you SSH access you can run top -c to see current resource usage of the server, and normally you can do an ls -lah on the home directory to see just how many domains are on your server.