If you are summoned to small claims court, can you leave the country for vacation?

If you want to lose by default and get a judgement levied against you then by all means.

Yes, you are not required to show up, if you don't, you just lose and they are allowed to do what they want.

Of course they may attach and garnish all of you money in the bank, so if you are on vacation somewhere you could find yourself stuck when all of your atm cards and money in the bank is gone.

My "two bits" is that if you don't make alternative arrangements when you've been served a notice to appear in court (subpoena, summons, appearance notice, etc)and don't show up the other two peoples answers posted to this question would be an accurate result. However it is typically very simple and flexible if you take the time to request an "adjournment" or have the matter set for a different date. This can be done by contacting the courthouse and explaining your situation and asking what you need to do to change the court date. This also shows your intention to take the matter seriously regardless of other priorities and will likely make the outcome much easier for you in the end. Cheers