Not at the bottom end of employment ladder. For low-skill jobs there are often more candidates than open positions, so almost everyone is expendable. For example, a food store on the corner of my street can, and has many times fired a clerk only to find a replacement within a day or two. At the low end of the job market there is always someone who is younger, has less integrity and/or is willing to put up with more crap than you - so you're completely expendable.
If enough people are angry about it, the employer will be forced to stop because they won't get enough candidates.