Dic: signal (in relation to someone and to doing something)

I found a sentence which reads as follows:

• Falling interest rates are a signal to society to adopt more capital-intensive projects with lower rates of return.

An interesting point to me is the semantic relationship between the proposition to(to society) and to-infinitive(to adopt). I wonder what the difference is between the following two sentences:

1. Falling interest rates are a signal to society to adopt more capital-intensive projects with lower rates of return.
2. Falling interest rates are a signal for society to adopt more capital-intensive projects with lower rates of return.

I look for what dictionaries say about the usages  in this case of signal.

▷noun 1: a sound or action that you make in order to give information to someone or tell them to do something.

 _ signal (for sb) to do sth:

• When she got up from the table, it was obviously the signal for us to leave. 
• The headmaster gave the signal to begin.
• At a pre-arranged signal the lights went out.

▷verb1: to make a sound or action in order to give information or tell someone to do something

• signal at: Mary signalled wildly at them, but they didn't notice.
• signal to: The judge signaled to a police officer and the man was led away. 
• signal for: He pushed his plate away and signalled for coffee.
• signal (to) sb to do sth: She signalled to the children to come inside. 
• signal that: The bell signaled that school was over.

..... LDOCE

The most close example to the case would be She signaled to the children to come inside.

It seems to me that the proposition for combined with to-infinitive in the sentence number 2 contains some meaning of duty or appropriateness with regard to society, which is similar to saying that:

• Falling interest rates are a signal that society should adopt more capital-intensive projects with lower rates of return. 

But how about the number 1?