It is true. The fuse tap will bend the contacts in the fuse box to accommodate the widened blade of the fuse with the tap attached. If you remove the fuse tap, the fuse will not make a good, firm connection anymore.
I prefer to use wire taps. If the circuit needs to be removed, you just cover the cut insulation with electrical tape. Here’s what a wire tap looks like. It’s color coded for the wire gauge size to insure a solid connection.
http://contentinfo.autozone.com/znetcs/product-info/en/US/drm/86503/image/2/