Adobe Form - How to send to a client not showing the fields in blue

That is a setting that each user has under Edit > Preferences > Forms > Show border hover color for fields (or not by unchecking the box).  You can put enter the following document level script and the field highlighting will be turned off when the user opens the form:

app.runtimeHighlight=false;

Keep in mind that this will change the setting on the user's system for all forms and not just the form in question.  Users might not appreciate a setting change that they didn't authorize and don't know how it happened, so it would be a good idea to warn them or give them the option.  Here's a modification of the script above that asks the user if they want this:

if(app.alert("Do you want to turn field highlighting off?",2,2)==4)
{app.runtimeHighlight=false}