No. An employer, if they REALY want to fire someone, can anyway. Your employee dead weight? Document it. Easy. Assign tasks, give a reasonable time frame, and then issue a write up should they not succeed. Is that somehow an impossible task for the poor overburdened employer? Got an employee with a bad attitude? Again, document it. Making trouble at work? Document it. In short, be present and proactive at you business.
Got someone you just don't like and want to fire? Schedule them for 6 hours a week, at the worst times, the worst jobs, etc. They'll quit in no time.
I really don't see what employers' problem is.