Although the tweaksets are written and provided for the most part by a Xara developer, they are done so completely independently and without any guarantee of support or fitness for purpose. In this way Xara are in no way obliged to support them or accept any responsibility if the use of one or more of them completely wipes out your web site. The way I look at it, I'd rather have them in this manner than not to have them at all, but once again, I do agree with you that they should, if at all possible, be integrated into the product. But for the time being they are marked thus:

DISCLAIMER: Whatever happens as a result of using this product, author is not responsible for this. Use it on your own responsibility. Copyright © 2009-2011 John W. Horn