Also, salaried generally means you get paid the same amount regardless of hours worked, which is another thing people seem to overlook.Except the spirit of that agreement to not worry about the variance of working, say, 35 hours one week, 45 the next. They still quite definitely expect you to work an average of about 40 hours -- and usually provide language in the employment/consulting stating exactly that. In fact, if your agreement mentions the phrase "full-time" it is universally understood to mean exactly that.
Many big/well known companies do not have issue with moonlighting.
Even when outside employment/consulting is allowed (1) the vast majority expect you to inform them of such arrangements and (2) they do not expect you to shorten your commitments of time + focus to the role they are providing you a ... full-time salary and benefits for.