As we can see in javadoc (say for 1.6)
java.util.Collections#synchronized* methods does not synchronize iterators!

As we can see in spec http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.14.2
java foreach statement uses iterator inside: http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.14.2

Let's make IDEA highlight any usages of iterators and foreach statements for collections instances that were created with java.util.Collections#synchronized*