Each event has a completely new and separate unique URL link to the Speedwaiver for that event. This is why having a guest register on MSR helps speed things up at waivers.
An alternative is for drivers to send their copy of the unique Speedwaiver link directly to their guests, so they can create and sign their own Speedwaiver ahead of time...again to speed things up at waiver station.
The least preferable option is also available, Waiver station has a QR Code guests can scan with their phone, go to link, fill out Speedwaiver, sign Speedwaiver, then get picture back for waivers to verify, then enter. All while people behind them are waiting in line ready with their Speedwaivers already done.