Don't prepare a will leaving someone $100 seeking to exclude them.

I am currently assisting clients with a probate for an ancillary probate of a will I had nothing to do with but 

it provided that one child was to receive $100 and the other two children were to receive 1/2 of everything else. It then left all the other property to pass through the residue. As a result we have had to try to get a consent from the client who was essentially excluded by his parent and is not cooperative. They can then refuse to cash the check and cause a lot of hassle in probating the estate when that could easily be avoided. 

Some have heard that you should leave someone a dollar or similar disposition and that would prevent them from challenging the document which it does not but it does require additional steps to have them sign off on the estate and takes a lot more time to close up the estate. In this case as in many like this the intent was to exclude and not even provide for them. A better way to have achieved this would just have been for reasons best understood by me I  make no provision for my child xyz. If it is desired to provide something for them then it can be relayed to the other children to give a token amount but without the requirements for the estranged child to cooperate.