I'm a web, database, and network architect based in NYC, with specializations in the financial services, publishing, and SaaS sectors.
I build complex Marketo integrations for companies large and small... and can make Marketo forms and emails do things you never thought possible!
Check out my blog at https://blog.teknkl.com, which has Marketo-specific technical insights you won't see anywhere else, along with wider topics from my programming and systems work.
IP issues?Doubtful. Changing your IP address will not invalidate or hijack someone else's cookie -- unless you (not Marketo) are using a misconfigured web proxy that does not vary...
The Munchkin cookie isn't appropriate as a GA User ID. It's far better to use the Marketo Lead ID unless it is definitively unavailable (as will soon be the case w/Anonymous Market...
The list is missing .MILL. That was probably a typo, but more important, there aren't enough exclusions. Needs to at least cover a-z0-9+=@,Consider:john.mil@example.comjohn.mil+ret...
When it's required/desirable to persist custom field values I like to use pending leads (as distinguished from both anonymous and named leads).Pending leads use the Munchkin cookie...