This is an unfortunate situation as one of the managers would have to have proof that that this employee was infact stealing tips. This is very difficult to prove and it does leave an employer wide open to be sued should they not have 100% proof.
Your employer is however wrong in stating they do not have recourse. In Colorado, employees not working under an employment contract are deemed to be "at will." At-will employees may be terminated for any reason, so long as it's not illegal.
What "at will" employment means is that any hiring is presumed to be "at will"; that is, the employer is free to discharge individuals "for good cause, or bad cause, or no cause at all," and the employee is equally free to quit, strike, or otherwise cease work.
If you employer believes your claims and perhaps other employees have complained about this co-worker, your employer could terminate her. Perhaps her work performance isn't stellar or she's had complaints from customers or other issues. Damaging company property is also an reasonable reason to terminate employment, but the managers would also need proof.
I would suggest that you recommend to your managers that this table be removed from the public area if the carving can not be buffed out. It is not good for business for patrons to have to view this vulgar grafitti and it is also not fair to you.
Hostile environment law does not prohibit simple teasing, offhand comments, or isolated incidents that are not extremely serious. Rather, the conduct must be so objectively offensive as to alter the conditions of the individual's employment. The conditions of employment are altered only if the harassment culminates in sufficiently severe or pervasive circumstances which would create a hostile work environment.
At this point, your managers must remedy the damaged table and assure that this co-worker does not begin to torment you verbally or in a retaliatory manner. Should her actions escalate then if your managers ignore the situation, then I would suggest you contact a local attorney
All sorts of things can create what employees deem to be a "hostile work environment". But, in the legal sense, a hostile work environment is caused by unwelcome conduct in the workplace, in the form of discriminatory harassment toward one or more employees.
in the eyes of the courts, a hostile work environment typically must be caused by discriminatory workplace harassment based on race, color, religion, national origin, disability, age or sex. Additionally, the harassment typically must be severe, recurring and pervasive
If this person has verbally or physically threatned you you can call the Pueblo Police. If you are fearful your car will be damaged, be sure to park in an area that is in a high traffic area in a well lift spot. Leave the restaurant with other co-workers, versus walking out alone.
Hostile Work Environment
Let me know if you have questions.