proof of presence for maker offers for instant payment offers

[charcharchar]

To avoid disappointment for when people take SEPA INSTANT or CRYPTO INSTANT or other similar offer types when the maker is not actually present to continue with the trade.
Suggest the offer goes automatically offline after a time period/20 minutes/ if maker is not present to answer an arithmetic or other proof of presence challenge. Just clicking a button could easily be circumvented.

[charcharchar]

Im thinking forcing the offer go offline is probably too harsh. The taker could be given the option to take it but let them know the maker may not respond instantly because they did not prove their presence recently.

[boldsuck]

SEPA Instant is 24 hours.
It is unrealistic that someone presses a button every 20 minutes. The effect would be: Makers would only offer SEPA trades.