@neo2551 It's common in the US to ask applicants if it's okay to contact your current employer, specifically to avoid those awkward moments. But other than that, I'd be prepared for employers to follow up on anything you put down.
It is odd, because then your current employer would know you might quit the company.
I should clarify: many applications I've filled out have asked me if it's okay if they contact my current employer. So if I don't want my current employer to know I'm shopping, I just check "No."
Those checkboxes don't usually apply to previous employers (not current).