Missy,
I've been in a situation where a 717 was pushed back from Bay 55 is on taxiway C at night in rain. We were given a clearance from bay 18 via foxtrot to the foxtrot holding point 16R.
ATC asked us if we could keep clear of the tug. Once we turned onto C, as we were directly behind the a/c and tug, all we could see was the flashing light. We couldn't see how far away it was, or even if it was moving.
ATC seemed to get agitated. We just did a 180 and went the other way around.
No big problem, they're just hard to see at night in the rain.