If your competitors are really watching then I'm sure they'll find out regardless of an email from you.
... but you are completely within your rights to remove them. I don't see an ethical issue with that (I mean I do see the ethical issue, but after thinking about it I do not believe removing them is unethical).
By removing you might by a little (or no) time before they find out.
Is it worth it?
Is what you have to say going to be a huge tip off?
At the end of the day, this is your startup, your job, your company and livelihood and completely your call to make.
... but you are completely within your rights to remove them. I don't see an ethical issue with that (I mean I do see the ethical issue, but after thinking about it I do not believe removing them is unethical).
By removing you might by a little (or no) time before they find out.
Is it worth it?
Is what you have to say going to be a huge tip off?
At the end of the day, this is your startup, your job, your company and livelihood and completely your call to make.
my2c