The lack of any legitimate data would flag it up as a security risk. Using Telnet without encryption to connect to a TLS service is a dead givaway that it's not legit since Telnet doesn't set up the TLS before the connection.
And just how do you imagine a TLS session starts? If you are using telnet to prove or disprove connectivity exists to a host, then the initial connection attempt is all you need, and that is the same for any tcp connection, whether it be a TLS negotiation or any other protocol.
I agree with you about ping, most secured environments block ICMP traffic nowadays, however, it and traceroute are still useful for investigating latency and routing so long as you temporarily enable it on the endpoint.