Andrea, as mentioned in the description this patch *only* supports boundary type filters (besides the limitations set on the layers as a whole), no other type of filters are supported as of yet. It seems to me this is better than supporting no data security at all and ignoring it all together. 

Therefore we do not generate a separate tile cache, but simply refuse to serve requests with bounding boxes that are not allowed. The behaviour is different from WMS, because we do not actually apply the filter. Otherwise, we are dealing with a much, much higher degree of complexity. If you however, use the integrated WMS, you will still get the correct, filtered, result (unlike is the case now) because the exception will forward the request back to regular WMS. This limitation was set on purpose to avoid this complexity and cut costs. Do you think a patch can be accepted with this limitation? Further development is perfectly possible, and this is definitely a big improvement, even just the basic layer security is a big improvement.

The MultiPolygon in CoverageAccessLimits and WMSAccessLimits should however also be taken into account, indeed. Will change that.