Avoid them by not breaking the law and do not violate employees rights. Stop looking at employees as prices of trash when they report misconduct in the workplace. There are a lot of bad supervisors out there even in otherwise good companies.
As far as deleting emails or destroying other documents and evidence it is against the law to destroy or tamper with evidence if the employer knows or should know that the material will be evidence in a claim or case.
If it is safety related I can also fall under OSHA 11(c) whistleblower protections. You only have 30days to file your 11(c) complaint so act on it fast.
