For many purposes, trusts are better and easier legal instruments to work with than wills. However, they can also be a difficult situation, according to the Wills, Trusts & Estates Prof Blog in "Preserving a Trust."
When a particular trust is easy to revoke or alter, it is easier for someone else to do so fraudulently. For trusts to be valid, they do not have the formal requirements that wills do. No one needs to be present to witness the trust being signed in most states.
That makes it possible for someone to fraudulently revoke a trust and create a different one that benefits themselves, because the lack of formal trust requirements may at the same time be beneficial and also create a hazard.
There are ways to guard against this possibility when creating a trust. This is one of many reasons why you should not simply download a revocable living trust form online. It is much better to go to an estate planning attorney, who can create a trust and help you execute it with some protections against fraud.
Estate plans contain important legal documents that should not be created lightly. An estate planning attorney can advise you on creating one that fits your unique circumstances.
Reference: Wills, Trusts & Estates Prof Blog (April 1, 2018) "Preserving a Trust."