Should proper nouns be capitalized when used as verbs?
- "I Googled it"
- "I googled it"
The dictionary observes via http://www.merriam-webster.com/dictionary/google
goo·gle transitive verb, often capitalized
So it's not regulated, but often is capitalized, except by the dictionary itself.
Now, if you're asking "should" proper nouns be capitalized with regards to maintaining justice for those who have achieved such fame or notoriety as to have their names become verbs, well then yes I believe the verbs transitively receive the proper distinction of being capitalized.
I believe that the pinnacle of glory is when your name is used without being capitalized. Such as macadam, from McAdam, etc..
When "Frigidaire", a trade-mark largely used in French instead of the correct "réfrigérateur", was accepted as a common name by the Académie Française, they were jubilant.
But Dr Guillotin was less pleased to see, during his life, "guillotine" becoming an only too common word ; in fact he didn't invented it, but was a strong supporter.