They weren't wide band jammers, but cell tower spoofers were known to be in place in Washington DC since at least 2014.¹ They were widely suspected to be operated by foreign intelligence services, which was recently confirmed.²

So "people will definitely notice", but if you're Israeli intelligence you'll get away with it anyway.

1 https://www.techdirt.com/articles/20171130/07551638706/senat...

2 https://www.politico.com/story/2019/09/12/israel-white-house...