Part of the signal reaches to within 75 miles of the stadium you mean. That's the rule. Not that it reaches Tampa Bay. Just like Jacksonville with their blackout radius. Orlando and Jacksonville proper you can't even make a case for them being within 75 miles of each other or either market picking up the others signal. However, Orlando's signal penetrates the 75 mile barrier therefore they are blacked out there too.
I know South of Tampa the nearest you can go is Naples/Ft Myers. North, due to signal penetration it is probably when you pick up Jacksonville channels.
That said, I've argued this for years now and will keep doing so until the rule is changed (so, until I die). If for example you live on the Space Coast of Florida, you receive Orlando locals. So, because of this you are blacked out if the Bucs or Jaguars aren't sold out. I think this is fine for the local stations. If they don't sell out, you do black it out to the masses OTA. However, if you are an NFL Sunday Ticket subscriber and they can determine by your zip code which is what they use to determine everything else that you do not live in that 75 mile radius which in my example you wouldn't, then I believe it should be available to SUNDAY TICKET SUBSCRIBERS in those areas.