Ofcourse VAT can be evaded. In countries like Pakistan, where businesses do massive unrecorded transactions, it will be very hard to implement such a system of taxation. Even the recorded transactions will be understated if threshold is set. And even if it can not be evaded, all the burden will pass on to consumers and prices would shoot up, which are already at high. Notion of taxation is that it controls distribution of wealth but some people are commiting suicides and some are getting richer and richer, showing violation of basic purpose of taxation. Its time for civil disobedience.