♯For example, Electrum has a list of 'official' servers available in the client IIRC. ♯
I don't know if we can call these servers official but there are a list of servers
hard-coded in the client. I may be wrong but this is possibly for finding an initial number of servers (similar to core and finding peers the first time)
Lauda is correct about that stuff. In addition you can handle some of the trust issues on your own by selecting the onion Electrum servers from the list. This allows you to stay anonymous even from the actual Electrum server you are using. Nobody in the entire route can sniff your traffic that way because there is no exit node.
The problem with using Electrum server (or generally a third party SPV server for any other wallet) is not revealing your IP. The problem are two things:
1) Privacy: For example with Electrum the servers see all your addresses and transactions and in case they keep log your privacy is compromised. In this case your IP is the least important.
Solution: use a full node yourself, use servers that promise no-log (not fool proof), use different wallets
2) Trust: When you are relying on a server to tell you about your balance, transaction, confirmation,... you must trust that said server is telling you the truth.
Solution: wait for more confirmation, change server, double check on an online block explorer
Some additional good information
