Muni Paper Transfers versus Clipper e-Transfers: What is Better?

One frequent complaint I notice on my Twitter feed is about the 90-minute transfer policy on Clipper cards and it being so strict versus paper transfers that can have an expiration that wildly varies, and in some cases at least two hours.

Let's do a comparison of the two transfers.

Muni Paper Transfers:

1. Issued at time of purchase, that is, if the passenger takes one.
   
2. Easy to show to fare inspector.
3. Expiration time may vary. Muni policy requires 90 minutes, but some drivers do not change the time too often, so they put extra time. Some may get two hours, while if a driver forgets to fix the time, a passenger may get a short expiration.
4. Easy to identify when it expires based on the time the transfer was cut.
5. If done using Muni, can give transfer to another passenger to use.
6. "Late night" transfers can be issued starting at 8:30PM and expires at 5AM the next day.
   
7. Mass printing of transfers for drivers every single day, causes littering (especially at terminal stops).
   

Clipper e-Transfers:

1. Automatically issued on first tag on reader. No need to ask driver for one.
2. Fare inspectors must use their card reader to verify validity (non-expiration).
3. Strict 90 minute time limit. No more, no less.
   
4. Not easy to identify when it expires. Only will show expiration time when tagged on their first transfer to another vehicle or station. Since Muni metro's "Proof of Payment" policy requires a transfer to be valid, it's hard to track when it will expire and a new fare must be paid. Passengers will need to use a stopwatch or keep an eye on what time it would expire. Clipper did admit there was a glitch causing some vehicles internal clocks to not be synced with all others.
5. If done using Muni, can't give away e-transfer on Clipper card with another passenger. But can if it's the last ride on a Limited Use Ticket.
6. No "late night" e-transfers issued. Muni rejected this at a past Clipper/TransLink board meeting.
   
7. No paper waste and littering.
   

Each option has their own strengths and weaknesses. I would take a paper transfer because I may get more time and can easily identify when it expires, but a Clipper card's e-transfer lets me automatically get a transfer and there's less littering on our streets. I live not too far from a bus terminal stop and I always see tons of transfer stubs all around the ground, even when there's a garbage can just feet away.

If I ran Muni...
I'd extend Clipper e-transfers to two hours because there's no simple way to identify when the e-transfer expires. Paper transfers would still be issued for people who pay with cold hard cash, as there's no way to fairly enforce the "Proof of Payment" system without some kind of fare receipt.