Depends. Always get the feel right, stop and start together, then it's up for grabs.
I have no problem playing the original bass line, or parts of, when it's needed. If it's a cracking line I'll be up for it, but many numbers don't have unique lines, so there's no point in slavishly following those. My attitude is, it's me playing in the band so you get me playing the songs not copies of the 25 original bassists.