You Can't Recruit Away Happy Employees - First and foremost, you can't recruit away happy employees. Surveys show that 50% to 70% of executives would make a move for the right job offer. After eleven years in the Recruiting business, my experience is that most people think they are underpaid and undervalued. In some cases they are correct; in many they are not. Most executives are actually being paid their market value based on their education and experience. So if a company has a beef, my recommendation is they should examine their culture and compensation packages. There is usually a valid reason the employees are leaving.
Top Reasons Why Executives Move On - The company is poorly managed, in financial distress, or has a poor company culture. Yep, totally get it! If the company is not well run and/or treats employees poorly, there is going to be employee churn. I have an "excluded" list of companies that I won't work with for exactly that reason - they are not a good place to work.
Personal Situations Can be an Exception - In several cases, I have helped friends make a move that has nothing to do with their current role. They were happy, but needed to move for personal reasons. A family member, usually a parent, has health issues and they need to relocate to help out. Or one of their children is off to college, and they want to be close to them. Maybe they five years before they retire and are looking for a nice sunny location.
You Can't Begrudge People for Moving Forward with Their Career - If someone is a Director at $125,000 and being offered a VP level role at $175,000, you can't begrudge them for progressing onward and upward. Yes, I know it's frustrating; however we all want to better our situation in life.
If You are Not a Client, You are a Sourcing Pool - Let me address "poaching." Executive Recruiters treat companies in one of two ways. If you are a CLIENT and sending a Recruiter business, they should NOT be poaching your employees unless there is a valid reason (see personal situations above). My contract specifically says that I am "hands off" of client employees and won't represent them for jobs. On the other hand, if you are not a CLIENT, then Recruiters are going to accept resumes from your executives and represent them. Why? Because they are paid to fill positions, and if you are not a client, you are in the sourcing pool.
Be Wary of HR Territorialism - There was once a Director, Recruiting that did everything in his power to keep me from working with his company. Unfortunately, he was not sourcing good candidates, and the "C" level executives above kept end running him and calling me directly. He was not happy, but is that my fault? This is a for-profit business that supports a dozen charities. It's what I do for a living. I'm not going to tell a CEO "no thank you" when he asks me for help. The Director, Recruiting was eventually terminated...and sent me a resume. Tip for HR executives. If you don't like external Recruiters, that is absolutely your prerogative. I'm not offended. But remember this; Executive Recruiters are going to give the big HR jobs to executives they know and trust. Why? First and foremost, because they know and trust them. Second, because they have supported the Recruiter, and the world runs on relationships.
The Proper Strategy for Recruiting - When I have a job, the first phase is to check my stable. Do I have someone queued up that is an exact match for the job description? Phase two is to put the job "on the wire" meaning I email 200 professional contacts for REFERALS. My specific verbiage is, "I have a CFO role at $300,000 in Las Vegas. I realize this is not a fit for you personally, however if you know of someone that would be a good fit, please point them my way." That is asking for referrals, NOT poaching. Had one executive send me a nasty email that I was poaching his employees. My response was, "First, I was looking for referrals. Second, and not to be disrespectful, but you don't have anyone on payroll that would make sense anyway."
There is no Upside to Getting Sideways with Executive Recruiters - Don't get nasty with Recruiters! The last thing you need is them targeting your company as a sourcing pool. They can, and will, recruit away your top employees. Personally, not my model, however not everyone is as kind as me. Like your Mom always told you...play nice!