I know I can omit logo by changing the “Style”.
(Change the style or edit it to eliminate or disable the watermark.)
When my.sketchUp is used as a viewer by clients it is a bit distracting due to its size.
Seems a bit of “overkill” 
Using it as a viewer implies you’re looking at an existing file. If you change the style to one without the watermark and save the file, the watermark won’t be displayed when you open that file.
OK DaveR, that will do it, thank you for the quick response!
On another topic, I agree with DanRathbun’s comment that my.sketchUp has great potential to aid education.
I am currently submitting a proposal to teach disadvantaged teenagers 10-15 yr old
in the local city library. The teens have free access to computers which can now be used
to teach basic modelling skills.