Are digital spread-spectrum microphones used? Traditional "just modulate the mic to 485.250 MHz" systems seem too jammable/hijack-able nowadays, while a digital frequency-hopping scheme is more resistant to interference, intentional or accidental, at the expense of some milliseconds of latency.
Just looking at the most expensive wireless solution on the Shure website: Shure AD4Q Four-channel Axient Digital Wireless Receiver: 4-channel Digital Wireless Receiver with 184MHz Tuning Range, Frequency Diversity, and 256-bit Encryption, $7500.
If a large production ever has an issue with someone in the parking lot (or elsewhere) trying to jam them, the cost of one of these systems feels like basically nothing. You'll spend more on renting chairs.
As someone who produces large scale events in major cities I can tell you it's still not a solved problem. In places like Times Square there's just so much RF going on from similar devices that you can see bizarre intermittent problems. That's the observation I'm using to assume it could also be done intentionally.
Which, of course, would be a massive problem with the FCC and a felony and all that. But technically it's still possible I'm assuming.
To answer your question yes, for sure large scale productions have the top end devices, and plenty of backups.
Just looking at the most expensive wireless solution on the Shure website: Shure AD4Q Four-channel Axient Digital Wireless Receiver: 4-channel Digital Wireless Receiver with 184MHz Tuning Range, Frequency Diversity, and 256-bit Encryption, $7500.
If a large production ever has an issue with someone in the parking lot (or elsewhere) trying to jam them, the cost of one of these systems feels like basically nothing. You'll spend more on renting chairs.