If you are referring to the QA concept of the Lean Process, my recommendation is to take every advantage of filling out surveys and contacting customer care for BOTH kudos and grievances. To go the extra mile, always ask for the GM's business card or e-mail address and send a personal e-mail regarding your stay. Because the core concept to Lean is to maximize customer value while reducing waste, focus your comments in these areas.
Agreed about filling out surveys and providing feedback. However, working in the QA area myself, its been my experience that it's extremely difficult for "service" industries/providers to implement Lean processes that can be financially beneficial. Yes, improvements can be made, but it's highly unlikely that the cost savings realized will be significant compared to the costs of implementing a Lean program. The only places I've seen Lean work effectively is in manufacturing processes - where something is being made.