Back in the 1950/60's, as the BBC was rolling out TV and radio services, some of the Welsh nationalists/separatists decided they didn't want such things in their country and took to vandalising TV and radio towers. Net result - no TV or radio for a day or two. And lots of grumpy family and neighbours with nothing to entertain them - kind of back fired on the miscreants.
Similarly in the early 1990's a company by the name of Orange had the audacity to roll out a network across Northern Ireland and in certain neighbourhoods its infrastructure was attacked. Collateral damage in some cases included TV and radio sites that had been operating for decades - resulting in the neighbourhood having no TV or radio. The miscreants got home to rejoice in their victory only to find lots of grumpy family and neighbours.
So, may I suggest that if a 5G service is attacked, all phone services in the surrounding area are either switched off, or severely degraded for a few days afterwards, with lots of local publicity that the poor coverage is caused by the mindless vandalism of national telecomms infrastructure? Obviously make sure Tetra is kept functioning though. The message will eventually get through to these numbskulls.