taM,

There is something not right about your experience. We have lots of models set up around here in rainy conditions throughout the year and we just don't see that phenomenon nor do we get reports from customers. Yes, the fabric stretches as night falls, or when it starts to rain but tightening the fabric after the stretch keeps it taut until takedown. There are certainly lots of variables at work, namely stake movement, line stretch (which should be about zero with the lines we supply), line slippage in the tensioners, collapsing trekking poles, and poles/struts that sink into the ground. How long have you had this and has this been the case every time you have used it? Can you email me photos of your setup and/or call--I'm not sure who you are--to discuss?

Thanks.

-H