It will display a warning and let you continue
No, it won't - and that's the whole problem. It prompted me to write this piece on re-enabling SSLv3 on Firefox which is probably the most heavily-trafficked post I've done on that blog.
Most of these devices will support HTTP and HTTPS. The posture of the browser developers is to blow up HTTPS support on SSLv3 everywhere, regardless of the risk profile.
There are very few people who are going to get $1100 to replace a PDU because the current one only supports SSLv3. As it currently stands, those people have to re-enable SSLv3 for the whole Internet on their browsers to admin their local devices. Pretty soon they will have to stop updating their web browsers entirely.
There are only two possible real world outcomes:
1) people will re-enable HTTP administration and start sending their passwords cleartext on their LANs
2) the very people in companies who do security work will be running outdated browsers, on purpose, to connect to their gear.
3) a million dollars will appear overnight in a company's budget to replace gear for highly theoretical risks
simply is not an option that exists concurrent with reality.
If the browser engineers had handled the situation the same way as self-signed certs, or even made a more complex UI to specifically whitelist certain hostnames or subnets, then we could have made a reasonable transition. But that would have been hard work with real analysis required, and why do that when flipping a switch and boldly posturing is more crypto-macho?
The very same people who jeered corporate people for staying on IE6 are creating exactly the same situation in regards to SSLv3. They may understand a narrow aspect of cryptography very well, but they completely fail to understand the security of complex systems. They are hurting the security and privacy we're working so hard to achieve. Jeers indeed.