It's easy enough to see an AV 'dot' against prims you own on the mini-map if you are at the same vertical height (because of the black outline on the dot)...but when you're not at the same height, the 'T' style indicators can be lost against larger areas of the cyan pixels. I've been surprised several times at my property after logging in, and missing the AV indicators on the mini-map.
Either a magenta color, or even allowing users to select their own choice in preferences (overkill possibly) may be very helpful to builders, and owners of estates / larger properties.
There is an existing feature request for this at:
http://secondlife.com/vote/index.php?get_id=1096
Like I said - nothing drastic...but if you're still reading, then a vote would be appreciated
Many thanks.