I second that. Happened yesterday. Twice.
I appreciate Uber has not limited it to pool only. This may be the overriding reason they limit the filter to 2 a day.
Used it 3 days in a row and it has worked on pool and non-pool rides. Its been very effective for long trips. Especially those I've had to deadhead on in the past(coming from home base into Seattle and returning from airport).
Hope that one day it will work for Lyft though they may be doing themselves a big disservice if they're only attaching it to Line requests. Seems like an odd approach to limit usage of a feature when the goal is to increase usage over the competition.