I concur. On my way to Naples in September, I had a planned 12 hour layover in MUC. I went to shower/freshen up and at lounge check in, asked about an earlier flight. The agent was incredibly helpful - told me to take my time and when I came back, she'd have everything ready, no bother at all. This has been my experience multiple times on LH (MUC-NAP, MUC-VIE, FRA-TXL - mix of front/back of the plane). I think policy is a no, but experience and some pleasantness plus a friendly lounge agent usually does the trick.