Perhaps 'goaded' is more accurate than 'tricked'.
I think "seduce" should be the word you are searching for, since there was nothing in the Ems dispatch that forced anything upon France or gave them the slightest reason to fear Prussian aggression. It was just a bait, something that France wanted so badly that they couldn't resist the temptation.
And even for a bait, it wasn't much.
As for 'join in'... Bismarck wanted a war. France wanted a war. Tensions were high. The mere fact that Bismarck fiddled with the text of the telegram was a serious diplomatic offence. I think it's entirely possible that the war could be averted, but I think it's more likely, in this scenario, that tensions escalate, and France is seen by the other parts of Germany as much less of an aggressor. In this case, Bavaria and company might not join a fight which Bismarck/Prussia had visibly engineered - even if France was the one who first declared war. Again, especially if Britain and possibly A-H are pushing hard to keep other players out.
Surely Bismarck made a deliberate provocation - so what? That trick could not possibly have worked unless France was not just hungry but starving for war.
Both belligerents wanted war, but only one was willing to start it, and that one was
France.
I honestly don't know why people keep pretending that France was a innocent victim. Prussia had given France everything they wanted and still France continued to demand more of submission and ended up declaring war upon the
false rumour that the Prussian king told them to shut up.
One version is "We can't commit to that forever because forever is a long time."
The other is "No, shut up."
The two are very different.
But neither version justifies the DOW. It was high time that someone told Napoleon and Benedetti to shut up.
In a world where such a flimsy excuse is a legitimate casus belli - let alone when it's not even true - the state of peace does not exist.
That's the thing - you say he's too smart for that, but then why did he doctor the telegram?
If there's no gain then it's a massive risk for nothing!
The problem is: If France is backed up by Britain, then
France will doctor something - or perhaps not even bother to justify their aggression at all.